Our FAQ was a bit out of date on this topic. I have modified it to read as follows:
If you want to change your username, or if you forgot your password, please please please do NOT do just register under a new username. Contact any Moderator, and we’ll be glad to assist you in getting your name changed. A list of moderators may be found here: http://boards.straightdope.com/sdmb/showgroups.php
We want people to be responsible for their posts. There is history and there are consequences to what you post. We do not permit “sock puppets” for exactly that reason – they are a way of not taking responsibility for what you post, and of trying to avoid consequences. That’s not acceptable here.
It’s similar with name changes. If you re-register under a different name, you’ve severed the contact with the old name. That’s not acceptable. We’re happy to change your name and it will reflect throughout your history.
Well, we’re happy to change your name once. Twice, you’d need a damn good reason. We’re not about to change your name every other week.
We’re not super strict about the once only name change, but as the FAQ says we’re not about to change it every other week. If you’ve changed your name in the past and it’s been a few years, that’s no biggie.