[throwawaypanda]

>After filtering 1,000 tweets per query, I barely found 10-20 real human users.

I am kind of surprised the number of human users is so high. I know a lot of bloggers of various sizes. To the best of my knowledge virtually all of them have hooked up one of the available services to post on their behalf. They either spend a little time scheduling out their tweets for the next week/month then forget about twitter until their schedule runs dry OR they set something up to randomly pick from some pool of blog posts and spam links.

Either way they then essentially never go on twitter again once things are up and running. The whole thing is full of bots talking to each other.