Maybe I'm just starting to "get" twitter?

I've been mostly a bemused twitterer, been the suject of a twitpic, and in common with most others saying "what is the point?" . I have been reluctant to connect twitter to my iphone in case I get floooded with irrelevant tweets. However on reading this "how to" brief , I get the idea is not so much to say "what am I doing"... which I expect many aren't too interested in, but to ask questions that trigger interaction. OK but what can you find out in 140 characters? Finally I saw a note from David Snowden on how he used twitter and I can see now that when one has generated a truck load of followers you can put them to use by asking them anything! Given a choice we would all probably like to use a human search engine because we tend to get qualifications on the information. One problem though .... would you want to follow someone who keeps asking you irrelevant questions like "what time does the next bus come". I guess Twitter might let you segment your followers .... but that starting to sound like hard work!