As if the more than 20 billion Web pages out there aren’t enough, a new startup coming out of stealth mode today called Attendi has come up with a new twist on “people search.” This is not to be confused with the type of people search that Facebook is getting into (actually searching for people—see also Spock, Wink, Zoominfo, WikiYou and PeekYou), or the type of people-powered search results that Mahalo, Wikiasari, and others are exploring (also known as social search). Actually, Attendi could more aptly be called chat search because it wants to search what’s in people’s heads as expressed through online chats. Attendi is launching at DEMO fall.

Attendi is half a social network, and half a knowledge database. Here’s how it’s supposed to work. Members, known as “Attendis,” will create profiles on the site describing their areas of expertise, hobbies, and interests, as well as adding links to their blogs, social networks, or simply Websites they identify with. The site, which opens in beta today, dynamically creates tags that define what each person knows and cares about (they can also add their own tags). It is built on top of the Lucene open-source search engine, and the Jabber instant-messaging protocol.

When someone searches for a topic on Attendi, what comes back as results are profiles of other “Attendis” whose tags match the search request. And if they happen to be online at the moment, even on another IM system, the other person can initiate a chat discussion with one of them to ask questions about that topic. “Attendi will just be a way to broker your availability,” says CEO Drew Rayman. Every chat is archived, indexed, and becomes fodder for future search results.

Attendi is based in New York City, and Rayman is also the founder of an interactive ad agency called i33. He plans on selling search ad sponsorships based on Attendi topics, as well as a live chat ad unit that only pops up when a company’s online customer service rep is at the ready to do a hard sell through IM. It’s that kind of in-your-face advertising, though, that might drive people away from an IM-centric search engine and never give it a second chance.

Making topic-specific IMs searchable is certainly a novel way to create a knowledge database. But Attendi faces a huge hurdle in getting anybody to actually use its system. What’s the incentive? There is no existing network of super-smart Attendis anyone would want to tap into. One way around this chicken-and-egg problem, though, would be to take advantage of free advice that tens of thousands, if not millions, of people are already giving away for free online in the form of comments that people leave on blogs. There is no easy way to search across those. (Startups like Big Swerve, which was in the TechCrunch40 Demo Pit, are already onto this).

Bloggers today install search boxes from Google or Eurekster to allow readers to search through their posts. Why wouldn’t they also install a way to search comments if it were available. Attendi would be better off trying to build such a service to gain traction for its technology. It could offer a way to power comments for blogs that would make those comments searchable both on that blog alone and across all Attendi-powered blogs. That way, those people who leave their opinions across the blogosphere in the form of comments would surface in Attendi search results. Tapping into blog comments would be a great way to seed its knowledge network.