I feel like thats a common misconception. It certainly not every single thought of mine, and very little substance even. It's nice because the whole system is async, so you can get to it when you can, if you want, care or not care. the barrier to tweet is non existent :)

I know. So maybe some tweets are interesting, they usually contain links to blog posts worth checking out. I'll get to them through Reddit or HN, maybe I just don't like to be so connected.

I know very few people (that I follow or care about), who tweet all their thoughts.

With search tools and things like Tweetdeck, following is not even that important. You follow a keyword, and it works wonders.