While being a searchable database of what is being said at a particular time is unique, it doesn’t take Twitter too far afield from Google, which is a catalog of the world’s recorded knowledge. Google looks back at what documents have been produced and can be surfaced, while Twitter looks back at what was said on a given topic.

Certainly there’s an AdWords-like business there, but, as Mr. Chaffee told us, Twitter has another “wild card.”

In the future, searches won’t only query what’s being said at the moment, but will go out to the Twitter audience in the form of a question, like a faster and less-filtered Yahoo Answers or Wiki Answers. Users would be able to tap the collective knowledge of the 6 million or so members of the Twitterverse.

This could be a big deal.

BTW, I am still a little worried about Twitter shutting off and/or charging for access to Search.twitter.com beyond e.g. a few days (right now it will only go back 7 days at times, presumably due to server loads during the day, etc.). What this means is that it will be more difficult/impossible to use Twitter as your own personal new form of social bookmarking like I have been doing of late.

What happens if you can’t get ALL of your links/tweets back out EASILY via search? Maybe they’ll at least leave your own tweet stream searchable to you (e.g. through the Web interface). But obviously there are no guarantees.