I don't know if I do this in normal conversation, but I think have a tendency to dominate gchats. I like to write (duh), so I just keep typing and typing paragraph after paragraph. The other person will be looking at other web pages, or step away from the computer to make a sandwich, you know, the usual stuff, and meanwhile I'm writing the next great American novel in the gchat window. They come back and the screen looks like this (actual conversation):

17 minutes
4:59 PM me: i decided at work today that i am going to write a soap opera about au pairs
5:00 PM this was after my coworker told me he knew one who crashed the host family's car
5:01 PM and another who had an affair with the husband and then the mom found out and told the agency that the au pair was hitting the kids so they sent her back to her country
then the dad paid for her plane ticket back and set her up in an apt as his mistress
isn't that a great soap opera!

And it just goes on like that, with more and more text for them to scroll through.

And I type really fast so I imagine it's hard to get a word in edge-wise.