One of the things I enjoy doing on Twitter is posting up something I'm working on, and then clicking through to all the profiles of the people who like, comment, or retweet my work. I stumble across an incredibly diverse range of people by doing this, many with conflicting opinions to my own, and many who belong to strange subcultures that I don't understand, but who were all drawn to my work for one reason or another.
I think there's definitely a danger of crafting a bubble for yourself if you choose to use it that way, but as a tool for discovering people making cool stuff who otherwise wouldn't cut through the noise on something like Google search, I haven't found anything better.
Over time you would get a 'pagerank for people' and could do awesome stuff with that, like 'You don't know XYZ, but 3 people you trust trust her, and this is what they tell about her:' ...
My trick now is to use Twitter to discover interesting people, and follow them there. Granted, it's not a search engine, but it's at least given me the ability to discover weird things again.