I just came across the question Feature request: vanity URLs. It's predicated on what is, to me at least, an interesting point. What do people use their SOFU profiles for?
When I'm logged in, I'll use my profile's main page to easily jump to questions I've asked or answered, or occasionally the favorites tab like a bookmark.
And that's about it. I don't use the other tabs — activity, accounts, reputation, prefs — pretty much at all. Certainly I never give out the URL of my profile; it's not a secret, but who would want to visit my SO profile? I'm curious what other people use their profiles for, and especially what's so important that they would want to have vanity ("facebook-style") URLs.