When Facebook allowed users to choose their own usernames, which could be then used to produce URLs for your profile and pages associated with it that made sense (the so-called Facebook Vanity URL Landrush), they warned users to “choose carefully,” as it was a one-time choice. They now appear to have backtracked slightly on that issue. Slightly is the correct term, we think, because while you can now go into your settings and change your username, you can only do it one time. While this allows people who chose