There's only one news item dominating the cycle today, and that's the death of Osama Bin Laden.

We've already covered the news, but one titbit that caught Sleuth's attention was the case of a Pakistani programmer who lived nearby. He was on Twitter at the time of the attack and his tweet stream makes remarkable reading.

Sohaib Athar, a 33 year-old computer programmer from Abbottabad, was on Twitter when helicopters carrying members of the US Naval Special Warfare Development Group, aka SEAL Team Six, came overhead.

"Go away helicopter - before I take out my giant swatter :-/" he tweeted.

Shortly afterwards he reported a large explosion that shook the windows. Then power was cut to the area, although this isn't unusual, he commented.

One of the helicopters was reported as shot down, although the US says it was hit by mechanical difficulties and blown up by the crew, and Athar noted that his earlier joke might have been in poor taste.

He said that the army had cordoned off the area and was conducting house to house searches. There was widespread confusion as to what exactly had happened, some locals reporting that a drone had been shot down.

As the news was announced he realised what had happened and his Twitter feed came to light as the unwitting witness to the story of the year. Skype was going insane, he reported, shortly after the official announcement, and the amount of interest was shocking.

"I am JUST a tweeter, awake at the time of the crash. Not many twitter users in Abbottabad, these guys are more into Facebook. That's all," he said.

Unfortunately Athar's account now appears to have been hacked, and is posting links to spam messages. Nevertheless, if genuine, it is a fascinating example of the reach of social media as a global witness.

Twitter has confirmed that it is moving offices after securing a deal over tax breaks with San Francisco government officials.

The company is already based in San Francisco, but had been threatening to move out unless it got a deal. Twitter will move to an office block on Fifth and Market, which is charitably described in one guide book as ‘up and coming,' and just one block from Sleuth's lair.

"We are proud that Twitter will be among the first companies moving into the Central Market area and will be playing a role in its renewal with the city and with other businesses, arts organisations, and the numerous community organisations that have been doing hard work in the neighbourhood for many years," the company said in a blog post.

"San Francisco's unique creativity and inventiveness is a part of Twitter's DNA, and we feel like we are part of San Francisco. Three-quarters of our employees who live in San Francisco are involved in causes and charities in the city."

What is sticking in some people's craw about this announcement is that Twitter was talking about leaving the city and moving out to the suburbs unless it got big tax breaks from the city - chiefly payroll taxes. So much for its being in your DNA.

Even if Twitter grows radically the city won't see much benefit in the rumoured five-year tax deal, and if the parsimonious ways of Twitter employees mimic that of management, the beggars on Fifth Street won't see much spare change either.

President Obama stopped in at Facebook's headquarters in Palo Alto today for one of his Town Hall meetings.

This meeting, dubbed Shared Responsibility and Shared Prosperity, focused on the future of the technology industry, education, the budget, funding for research and the role of immigration. Obama took questions from guests and the public online in an hour-long Q&A.

VIPs, including senior politicians and Silicon Valley management, arrived with some very professional looking security early on.

Facebook staff filled every available crevice of the hall for a chance to hear the president speak. There were more than a few cameras being carried in by the lucky few.

The regular White House press contingent looks less than impressed with the whole arrangement. Predominantly based in Washington, they'd had a late flight to get here.

Security was tight, with lots of dark-suited watchful men with very visible earpieces.

Attendees may have been told to get ready nearly an hour early, but when the VIPs start arriving things are ready to kick off. Surprisingly MC Hammer was one of the first to arrive.

Gavin Newsom, California's Lieutenant Governor, was joined by Nancy Pelosi, minority leader of the US House of Representatives.

The event kicked off quickly, both men walking swiftly on stage, losing their jackets and getting down to business. A visibly nervous Mark Zuckerberg swigs from his water bottle.

Obama began the meeting with a little joke, pointing out when he first met Zuckerberg the chief executive was visibly uncomfortable in a shirt and tie. Now he and Zuckerberg were the only two people wearing them.

In discussions over the differences between Democratic and Republican priorities the president was robust, saying the opposition wished to "change the social contract".

After an hour's discussion Obama walked one side of the arena greeting fans before waving goodbye and disappearing off to a fundraising dinner where every guest is paying £38,500 to eat, and listen. 

Thereare burly men in dark suits and earpieces all over Facebook's Palo Alto headquarters today, as President Obama comes to the company to hold one of his Town Hall meetings.

This meeting, held with staff at Facebook and VIPs in attendance, has been entitled "Shared Responsibility and Shared Prosperity." Members of the public have been allowed to contribute questions, but not vote on which ones the president will answer. This is presumably to stop endless questions on drug legalisation that have been a feature of previous such meetings.

The president referenced Facebook as an American success story in his last State of the Union address and met Zuckerberg at an exclusive dinner for the heads of Silicon Valley earlier in the year. Co-founder of Facebook Chris Hughes is also a friend, after he ran Obama's social media campaign in the election that brought the President to power.

Of course, this isn't the only reason Obama's in town. Tonight he'll head into San Francisco for a fund-raising dinner, organised by Salesforce.com's chief executive Marc Bennioff. Sadly Sleuth won't be there - the price of a single seat is $38,500. Then it's off down to Los Angeles for another fund-raising bash tomorrow night.

The Town Hall is set to start at 1:30pm Pacific Time (9:30pm GMT) and Sleuth will be reporting it as it happens.

12:02pm Arrive after getting lost on the way. Turns out it wasn't too hard to find, just follow the satellite trucks. There's a huge media presence here.

12:05pm There's some anti-war demonstrators outside the main entrance - I recognised a couple of Code Pink protesters reminding Obama he has two and a half wars on his record. Everyone's being terribly polite however.

12:15pm I have press accreditation and, after a security wanding by a very large armed man, am let in.

The first thing to note is this is a small event. Press take up one side of the room, VIPs another and the rest are for Facebook staff.

12:35pm Oddly, considering the location, the Wi-Fi here is appallingly bad.

13:10pm The traditional request to silence the phones, since the event is about to begin.

13:25pm The VIP section is filling up. Publisher Tim O'Reilly is there, as well as San Francisco's former major Gavin Newsome, and MC Hammer. Are these the people too cheap to splurge on dinner tonight :)

13.35pm OK, we're hearing from Twitter that the president is running late.

13.37pm Just been extensively sniffed by a huge German Shepard dog. That's why they didn't check my rucksack on the way in.

13:54pm We're on. Chief operating officer Sheryl Sandberg welcomes Obama. She said been fortunate to work with him, the man with 19 million Facebook likes. Nancy Pelosi is also present, Newsom gets a shout-out, along with three US members of the House of Representatives.

13:56 Zuck takes the stage. Makes the case that Facebook is key to politics.

Zuck's just corpsed, saying he's very nervous.

13:58pm Enter Obama. Working the crowd like a pro. Huge applause.

He thanks Facebook for hosting, and says he's the only one in a jacket and tie here. He jokes that the first time he met Zuck he told him to take his jacket off, and has just suggested it again. It is very hot in here under the lights.

14:00 Facebook is all about connecting people Obama said. Democracy depends on an informed populace and Facebook means this isn't a one way conversation.

He says the times are more tumultuous than at any time in his lifetime. The worst recession since the Depression that we are now coming out of. There's also technical adjustments that need to be made. High unemployment is difficult.

Internationally there are generational challenges. Climate change can't be solved by one nation, and we don't have the institutions to do that.

But whenever we've faced challenges like this Obama said, we've always been able to adapt, change and get ahead of the curve. That's true today and Facebook is cutting edge. There isn't a problem we can't solve.

14:04pm Zuck gets the first question, and he asks about debt. What's going to get cut?

Obama responds that Clinton left the government with a surplus. Then we had ten years where we forgot what created the surplus. Had two wars not paid for, a huge prescription drug plan not paid for and we had a trillion dollar deficit annually, and massive interest payments. Then the recession started.

There is about $4tn of spending we need to cut. Obama proposes cutting around two trillion dollars in spending cuts and will get another trillion from reforms in the tax system to make people like Zuck pay more tax. We want to go back to the rates when Clinton was president. These will still allow us to spend on basic research, into education and energy. We can invest in next-generation wireless and broadband.

Still have problem with Medicare and Medicade. Obama wants reform - we spend more than anyone else on healthcare and we get poor results. Readmissions rate need to be cut - 80 per cent of problems come from 20 per cent of patients.

The Republicans don't want any new taxes, wanting 70 per cent cut in research into clean energy. They also want to make Medicare into a voucher that covers part of the cost and consumers carry the extra health costs. We need a basic social safety net.

14:15pm Next question is on the housing market.

House market is the biggest drag on the economy right now Obama says. A lot of people's homes are worth less than their debt. People who want to move can't sell, and people trying to buy face big problems. That said, there are some people who are better off renting he said.

The days where it was easy to buy a house with no money down are over. We need the housing market to recover, as people will have more confidence. It is getting better for buyers, but it's varied.

14:19pm Question from a Facebook employee, sitting next to someone in an Obama tshirt. Good video shot - coincidence?

14:20pm My first job on day one was dealing with the recession Obama says. We made sure we minimised the effects, making the biggest investment in infrastructure since the freeways (motorways) were built. When Obama came to office only two per cent of advanced battery technology came from the US- and such batteries are key for clean travel.

The economy is now growing, two million jobs created by the private sector. But we also need to tackle the deficit. Investors need to be reassured. We have to hit the accelerator but can't let the car slip backwards. If all we do is cut, with a machete instead of a scalpel, it will make the deficit worse.

14:24pm Question for the University of Florida on the DREAM act and immigration. Praises work of Sandberg for working on this at Facebook.

People who were born here to illegal immigrants and who were of good character, then why wouldn't we want to embrace them? Immigration is always complicated. We are both a nation of immigrants and a nation of walls, and the walls have been too high. Immigration makes us strong because ambitious people come here and that dynamism keeps us young and propels our progress.

We want to fix the whole system. Make legal immigration more efficient, which is of interest to Silicon Valley. If smart people come here why would we want to send them away? These are potential job generators. We want more Andy Groves here, we don't wanting the next Intel started in China. High skilled immigrants come here to study, let's make sure they can invest in America.

Also have unskilled workers who are living in the shadows, in agriculture, kitchens and helping to build America. But they are scared and feel locked out. They should pay a fine, learn English, but there should be a pathway for them to become legal. We will have to change the law but we can make it happen.

14:32pm Another Facebook employee question on the Republican budget plan.

Obama says Reupblican budget is radical, but not necessarily couragous. The Republicans want to change the social contract. I wasn't born wealthy, went to college on scholarships, Mum had to tak food stamps and my grandparents used Medicare.

The Republican budget cuts taxes for corporations and the wealthy and cut a quarter of the education budget among other things. You could call that bold, I call it short-sighted.

If you're a start-up company you can't get health insurance. If you have a pre-existing condition insurance companies won't take you. We want to cover everyone and make the system more effective. The government will save money and so will you.

14:40pm Question on education. Is an overhaul needed?

Zuck interdicts that the Race for the Top programme is the best thing the administration has done.

Obama said the argument was always the left saying we need more money, and the right saying we should blow up the system. People are recognising we need money and reform.

Race to the Top is simple. Most federal dollars are allocated to a formula based on your circumstances. We took one pre cent of total spending and made it dependent on reforming the system. Every school district could apply with a plan to develop their schools, with accountability and that you measured progress. Sort out drop-out factory schools. Over 40 states have initiated reforms, some of the biggest ever seen.

It all relies on good data, and we're starting to see real progress on the ground. Want a new law to reform schools by 2012. But government alone can't do them. When Silicon Valley complains about not having enough engineers then we need to change things.

Need to get more girls in science (huge cheer), more minorities and more new students all round. We need to make science cool, we want people to feel about the next clean energy source the way the last generation felt about the space race. We need to buckle down and get this done.

14:47pm Another Facebook question - debt and healthcare, how to reduce both.

I want to reduce costs Obama said. Take health IT. Heathcare is one of the few areas where a lot of stuff is done on paper. People are still using clipboards. The reason is because a large chunk of providers aren't automated.

The best healthcare is the Veteran's Administration because it's fully integrated and they can save costs that way. Obama describes the current situation as inefficient because there is no opportunity for efficiency. We want to change how people are reimbursed.

For example, if you cut hospital infections, then you can give bonuses. That saves money, but it takes time. We have a private sector system, so it's not something we can do overnight. But it will save everyone money.

14:54pm Final question - what would you do differently?

Obama says it's early days. Says sometimes he worries he doesn't explain things clearly enough. Healthcare was a huge battle. I do think that it was so complicated that at a certain people switched off. I've asked if we could have got it done faster. I'm not sure I could have - there's a reason it takes a hundred years.

In terms of what he needs to get done. Deficit control needs to happen, immigration is important, energy too. $4 a gallon gas hurts a lot of people. If you're driving 50 miles to work and you're stuck in an old beater that does eight MPG then gas prices are killing you. We need to invest in new approaches for energy. We need to invest in solar and wind, biofuels, converting the federal fleet to fuel efficient vehicles.

The treasury loses $4bn a year in subsides to oil companies. No-one's doing better than Exxon, except maybe Facebook. They don't need that money, so why not invest it in new energy.

You don't get cynical about our democracy. It is frustrating, and some of you feel it too. Just remember we have been through tougher times and we've always come out on top. We have best universities and workers, we are entrepreneurs. If we come together we can solve these problems, but I can't do it myself.

We've got a lot done since election day, we have made progress. So I hope everyone is prepared to double down and work to solve problems. Especially the young generation that needs to give a push. If you put the same effort into Facebook as you do with the country there's nothing we can't solve.

15:03pm Zuck gushes and gives Obama a Facebook hoody, which Obama describes as high fashion. Shakes a few hangs down far side of stage.

President exits stage right.

The FBI has shut down three of the most popular online poker services, and brought indictments against 11 senior executives for bank fraud, money laundering and illegal gambling offences.

Almost all forms of internet gambling using real money are illegal in the US since the passage of the Unlawful Internet Gambling Enforcement Act in 2006. None of the three companies is based in the US, but they do accept US players.

"As charged, these defendants concocted an elaborate criminal fraud scheme, alternately tricking some US banks and effectively bribing others to assure the continued flow of billions in illegal gambling profits," said Manhattan US attorney Preet Bharara.

"Moreover, as we allege, in their zeal to circumvent the gambling laws, the defendants also engaged in massive money laundering and bank fraud. Foreign firms that choose to operate in the US are not free to flout the laws they don't like simply because they can't bear to be parted from their profits."

According to the FBI the companies found most banks unwilling to handle the cash of US customers because of the illegality. The accused set up shell companies to obscure the origin of the funds being transferred, but some of these accounts were tracked down and frozen.

The companies then decided on a more direct approach. According to the FBI they paid $10m for a 30 per cent stake in a small private bank in Utah named SunFirst. The vice president of the bank agreed to process the funds from gambling sites directly, in exchange for a $20,000 personal bonus for his trouble.

"These defendants, knowing full well that their business with US customers and US banks was illegal, tried to stack the deck. They lied to banks about the true nature of their business," said FBI assistant director Janice Fedarcyk.

"Then, some of the defendants found banks willing to flout the law for a fee. The defendants bet the house that they could continue their scheme, and they lost."

The FBI confirmed that it had arrested three of the men named in the charges, with the other eight being sought overseas. Five domain names used to run the sites have been taken over, and courts have issued orders to freeze 76 bank accounts in 14 countries thought to contain as much as $3bn from American poker customers.

It's been a long time since Sleuth strapped on a woggle and went out into the woods with the Boy Scouts, but the organisation founded by Lord Baden-Powell is now making a play for the technologically minded.

The Boy Scouts, which Tom Lehrer described as "those noble little ... bastions of democracy, and the American Legion of tomorrow", is appealing to the scientific with a new series of achievement badges aimed at students of the digital era.

Among the new merit badges is one for robotics, part of the Boy Scouts' science, technology, engineering, and maths programme.

"The Robotics merit badge is an example of how Scouting remains true to its roots to help young people be prepared," said Bob Mazzuca, chief scout executive of the Boy Scouts of America.

"While the guiding principles of Scouting - service to others, leadership, personal achievement, and respect for the outdoors - will never change, we continue to adapt programmes to prepare young people for success in all areas of life."

The organisation said that as many as 10,000 Scouts could apply for the badge, which requires them to design, build and test a robot safely and attend or research a robotics conference.

After much competition Kansas City has been chosen as the first US location for Google's foray into building networks.

Last year the search giant announced it would build 1Gbit/s fibre optic broadband networks in US metropolitan areas. A test network was set up in Stanford, conveniently down the road from Google's headquarters, and today the company announced that Kansas would be the first test-bed for a major network rollout next year.

"Over the past decade, the jump from dial-up to broadband has led to streaming online video, digital music sales, videoconferencing over the web and countless other innovations that have transformed communication and commerce," Google blogged.

"We can't wait to see what new products and services will emerge as Kansas City moves from traditional broadband to ultra high-speed fibre optic connections."

The choice is a good one. Kansas City is a split city, as it's sited on the border between Missouri and the state which bears its name. Google can see how the two states react to the new network on a user basis and from a legal perspective.

The decision will go hard for a community not too far from the city, however. Topeka, a few hundred miles down the flat roads of the state, actually changed its name for a day to Google in order to get the search firm's attention. A cute PR move, but ultimately fruitless.

Sleuth thinks Google's reasoning on this move is clear but slightly muddled. The more people use the internet the more revenue will come to Google is the thinking, but the company isn't really a network operator.

That said, having this kind of fibre network that's open is a positive step. Too much of the US broadband infrastructure is with uncompetitive little cartels, and an open network could spawn real innovation.

Paul Baran, one of the original developers of the packet switching systems on which all internet traffic is based, has died at home in Palo Alto.

In the early 1960s Baran, a naturalised Pole, wrote a series of papers for RAND looking at network resiliency. After a series of tests he determined how the loss of network nodes would degrade performance, and proposed a solution whereby data was split into packets that could reroute around damaged parts of the network by using redundant capacity elsewhere.

At around the same time British computer scientist Donald Davis was developing a similar idea, which he called packet switching. Baran never claimed to be the inventor of the concept, but rather saw it as an idea whose time had come.

""If you are not careful you can con yourself into believing that you did the most important part," he said in a 1990 interview.

"But the reality is that each contribution has to follow onto previous work. Everything is tied to everything else."

The concept wasn't popular at first. Baran took his idea to AT&T, which said it was inefficient and unworkable. However, the US military did take an interest and Baran worked for them with Leonard Kleinrock and others to build Arpanet, the precursor to the modern internet.

"Paul wasn't afraid to go in directions counter to what everyone else thought was the right or only thing to do," said Vint Cerf, a vice president at Google who was a colleague and long-time friend of Baran's.

"AT&T repeatedly said his idea wouldn't work, and wouldn't participate in the Arpanet project," he told the The New York Times.

In recognition of his pioneering work Baran was awarded the IEEE Alexander Graham Bell Medal, a National Medal of Technology and Innovation and inducted into the National Inventors Hall of Fame.

After leaving RAND, Baran set up a variety of companies, primarily in the computer networking field. The last was started to investigate using housing wiring to deliver data. He is also credited with inventing the modern metal detector.

Baran had been suffering from the effects of lung cancer and died at home from complications. He is survived by his son and three grandchildren.