That's been one of the big debates circulating through the Twittersphere / blogosphere since Loic LeMeur kicked off the conversation over the weekend. I haven't had the time to weigh in, but Neville Hobson put up a good post about two search sites: Twitority and Twithority. (And yes, there are two web sites that do almost exactly the same thing that have a one-letter difference in their domain names!)
In my own brief testing, I rather liked how TwitHority provided a two-column view of results by ranking and results by time. Nice to see. On the other hand, I liked how Twitority (no H) provides a Technorati-like way to search by degree of authority (although I have to wonder what they set a "lot" at, as it never turned up results for me).
Personally, I do like the option of being able to rank search results by number of followers. Yes, I understand that the number of followers is meaningless in so many ways... and that it can also be gamed by someone who, for instance, sets up tons of bogus twitter accounts. I realize that it's a very imperfect measurement. Still, it is a measurement that's out there. And the fact remains that if someone tweets something about you or your product/brand/service out to 10,000 people, odds are pretty good that it will potentially be read by more people than if someone tweets it out to, say, 20 people.
We'll have to see how these sites work out... but in my mind I'm glad to see someone trying to help us make sense out of all the data out there.