Once I got to about 1,000 followers on Twitter. I noticed that something changed. I used to Tweet, and not get much of a response. And if I did, it was from people I knew.
Just a couple days ago, I tweeted that I was in the Atlanta airport (with a link to a photo). A few months ago nothing would have happened. But now I got a number of replies and carried on a couple mini-conversations - all with people I have not met in real life.
I continue to be surprised by the entertainment / community / usefulness of Twitter as my network grows. So, follow me on Twitter! I'll follow you back.