The Internet Is Forever.
I don't use my real name because, while my name doesn't have any sensitive personal information attached to it today, someday there may be enough various bits and pieces to pose a risk to my privacy. Nothing goes away anymore! A hometown mentioned here, a job there, and birthday somewhere else can all be easily threaded together using search engines to form a worrying whole.
I already have my real name and (formerly primary) email posted online, because someone took a college form I filled out 13 years ago and put it in a searchable database online. Nobody asked me - I didn't even remember filling it out! But anyone who knows my name (which, unfortunately, seems nearly unique) can now Google it and get my email - whether I want them to or not. So if I used my real name here, and then sent an email from that address to a potential employer...get the picture?
Erick - with all due respect, expecting people to be totally comfortable with having buttloads of personally identifying information available to essentially everyone in the world, forever, is a bit naive IMO. Especially given the controversial nature of the topics we discuss here.
Oh yeah - ask Kim duToit how having his name associated with pro-gun polemics worked out for his startup business.
For those who can afford the luxury of totally transparent internet dealings - great! More power to you! But I think most of us are being smart, not cowardly, in anticipating that having every single post, web page, or blog entry that we ever make in our entire lives follow us around forever might someday come back to bite us in the rear.