The team over at Facebook has enabled the ability to create your own unique username, which then allows you to direct people to a vanity URL like http://www.facebook.com/username.
Twitter users should be fairly accustomed to this treatment, as that’s the way Twitter has been set up for quite some time (possibly since it’s inception). The major difference, at this time, is the fact that Facebook still requires you to input your e-mail address to actually login. Therefore, the only major change is the vanity URL. For most people, including myself, this doesn’t seem like that major of an upgrade to the Facebook service. Still, it makes it easier for people that spend a lot of time directing people to their Facebook pages.
I look at it as kind of the difference between giving someone your phone number and telling them to look you up in the phone book.