I think one advantage of the requirement of using a real name is that it encourages people to engage one another on a more human level. I like knowing your real name and some other users’ real names. It’s interesting – I have this impulse to write, right now, “I’m ____, by the way; pleased to meet you” – which I’m not going to do because I am extremely hesitant to share my real info on the Internet – but I think it illustrates my point, that it seems to me like this would be our “actual” introduction, despite the fact that I’ve known you for years.
The advantage of making people keep the same name seems obvious to me – even here on Fluther, where people tend to pick a pattern of names, name changes often become confusing. When I look at old threads the @ links become disjointed due to name changes. And I would never have known Mama_Cakes is the same person as Jude, for instance, if I had hopped back on the site a few months later than I did. And are you sure about the one-time name change thing? What about all of zen’s names, or CyanoticWasp’s? Or is that because they abandoned the old accounts? At any rate, it gets confusing.
I think the advantage in allowing people to change their names at will is that they want to, and sites live by catering to what people want. It’s interesting to think about the disjunction between real names and screen names – people change, and feel like they should change their sn to go along with it. Or they don’t think they got it right on the first pick. But these concerns rarely make people want to change their names in RL. One could argue that people are simply less attached to their online identities, but I don’t think that is the case – I am very attached to being wildpotato, and I know others who are likewise invested in their Internet selves. I think it’s a matter of the online identity being something that is supposed to be more fluid – something we can play with in a safe way, in this particular environment. Because it’s not very safe at all to play with one’s own identity in real life.