Right now, I have 2653 RSS subscribers and 890 Twitter followers.
Assuming not every one of my Twitter followers follow my blog via RSS, I'm going to say that puts Twitter penetration in my blog audience at about 25%.
If you're not on it, check it out, particularly if you just don't get it.
What's the point of it? It's a short form conversation that's going on between blog posts. Think if it this way: It's the "hallway track" at a conference--when the best conversations are the ones had spontaneously over on the side, away from the main exhibit room.
So before you think about whether you want to publish when you brush your teeth to the world, think about it from the listening perspective. You spend the time to read my blog, where the posts are often entirely too long--why not find out about what I'm thinking and who I'm talking to when I'm not blogging?
It's time to listen in on the hallway track. I'm here on Twitter: http://www.twitter.com/ceonyc