I hear that some people read their entire twitter stream. The whole thing. Without ever giving up and saying "sod this for a game of soldiers" and scrolling to the top. I know I "need" twitter, like it or loathe it, it's taken over from mailing lists and RSS feeds as the fastest way to stay up to date with the web dev world, after all we invented the web, not surprising we use it more than anyone else.
I currently follow 227 people, after one of my monthly culls. I estimate I read/skim about 10% of the stream, and from what I do read, 1% is relevant, 99% is crap. And I really mean crap. Insights into the personal lives of people I don't know is just noise, the link to the interesting and helpful article about responsive design? That's signal.
The day someone invents a usefulness filter and sticks it on Twitter I'll be a happy man.
Oh and if I could figure out how to remove all the spammy followers, I'd probably follow more people, as I'd follow back the interesting people who follow me, but who get lost in a sea of media drones, marketing bots and special deal tweeting machines for countries I don;t even live in.
Sort it out Twitter :)