In the hour-long presentation Facebook wasn't mentioned once, pretty impressive considering it's the market-leading social network. It was only at the Q&A session at the end that anyone could mention the elephant in the living room.
When the question was asked Brin ducked it, but his answer did reveal something of his intentions.
It seems clear that Google will be attacking Facebook on two fronts. Firstly, the basic Buzz will compete for user's time directly. One of the speakers admitted to using Facebook himself and I'm willing to bet a fair proportion of Google's 20,000+ employees aren't going to be trashing their accounts any time soon.
Secondly however, and this is something Brin pushed hard, is going to be a focus on Buzz as a business tool. He dismissed Facebook (without mentioning it by name) as focussing on friends and fun, while extolling the virtues of Buzz as a productivity enhancer in the office.
He gave the example of his writing an analysis article and mailing it around colleagues for advice. It's perfectly possible to do this now of course but Buzz will make that kind of collaborative working a lot easier.
That said, I can see considerable resistance to this in some areas from employees, particularly on the geotagging side of things. Google made a big point about privacy settings and how you can tailor your output to suit the audience but I can see companies insisting on staff leaving this on.
So you can kiss goodbye to calling in sick and sneaking off to the park on a sunny day, not that the Sleuth would ever condone such a practice. Salesmen on the road will be constantly available to be checked up on and employers will also no doubt be looking at any interviewee's Google profile when hiring.
But Facebook isn't the only company that should be worried about Buzz. Online reviews site Yelp, which last year Google reportedly tried to buy for $500m, could also be in trouble.
Google demoed using Buzz on a mobile phone to check out nearby restaurant reviews in an interface that Yelp users would recognise instantly. It looks like Yelp's owners could be facing the kind of regrets Jerry Yang knows only too well.
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