People keep wanting to have profile pictures of their "real" selfs and talk about their private life with the same people they write code with. That didn't use to happen. Back in the day, there wasn't even any avatars, just emails! Then people started using nicknames, that was fine. And first when avatars appeared, we used images of something else. Myspace and Facebook brought up the whole "I have to be the same person I'm online as I'm in the real-life" syndrome, and now we have what you described above.