People are far enough removed from each other on the internet. Knowing who posted something tells a lot. For example, I've been browsing HN about 3 months and I already know to pay extra attention to what tptacek on security. I believe people have gotten jobs from Hacker News too based on their reputation. I think HN is a great community and implementing this would just weaken it.
I believe I read about one here a few months back. Sorry nothing concrete. I know if I am ever in need more help, I'd go through networks and then ask around here.
