Handles are a reality for at least 3 reasons
1. It is a login - therfore likely to be duplicated in a large forum, Dave Smith 12 as a name would be tedious for Dave and his twelve namesakes. Most companies adopt anonymous user ids to prevent people guessing the owner and using knowledge of the person to guess the password, if you know Daves wife and kids' names you stand a fair chance of guessing a lazy password.
2. Using your full name (first and surname) will easily reveal your email address, a quick poll to see who likes which ISP will tell you the domain, then it is likely that the email will consist of first.sur at the ISP. There are plenty of robots searching forums to glean precisely this information.
3. Not everyone wants to be identifiable - when you first join a forum you have no idea how friedly a place is. there was a recent report on the BBC of a guy, who having had an argument on a chat room, was traced from information he had posted over time and was assaulted by the other person, 3 blokes, baseball bats and knives.
Not likely here, but at the end of the day, after you have been around a while, you know most peoples real names anyway.
I'm sure Jaime wont be offended by your post

Merv