Interview: Blekko co-founder and CEO Rich Skrenta

Rich Skrenta is the co-founder and chief executive of the Blekko search engine, which is looking to refine search results to eliminate URL spam via the use of slashtags.

V3.co.uk caught up with Rich and asked him a few questions about how the new system operates.

Your philosophy of search is based around slashtags. How does that work?
A slashtag is just a list of sites. For example, the 'health' slashtag is just a list of around 100 of the best health sites that we've had people review. We've made a couple of hundred slashtags and are watching as users generate new ones.

We're applying the Wikipedia model. Users can make their own additions and put on sets of sites to a slashtag, and in doing so can be invited to become a co-editor. People can also apply to edit other slashtags. People will check on each other's content and refine the results.

Your web search footprint is smaller than Google's. How important is that to the effectiveness of search?
We have a three-billion web footprint which we're constantly crawling and indexing, so our rankings are pretty good. Now that's not as big as Google it's true. But three billion is a lot of pages to go through if you know what you're looking for.

With slashtags you can refine the results. For example, if a search result brings up a lot of health spam then we know that the topic is health related, so apply the health slashtag and show the results from those sites that are trusted, rather than those put up in SEO [search engine optimisation] efforts.

SEO techniques are now commonplace. Are they having that great an effect?
It's a huge problem. The Google algorithm for page ranking really worked well in 2000 with the invention of social search. Back then there were one billion URLs and they were in the large part authored by humans for humans.

That's not the situation 10 years on. Now you have over 100 billion URLs and the majority have been created by a machine or by people with little interest in what they are producing. There are 20,000 articles put out on the web each day and we see accelerating trends in this area.

I remember when Hotmail first announced that 95 per cent of all emails were spam. What happens when 95 per cent of URLs are like that? At this point, the chance you do have is to go to trusted sources.