At 8:40 CDT on 31 August 2007, I joined Facebook. And then did nothing with it for several days.
I didn't add any Facebook friends until September 4th.
My first post, on September 5th at 7:43 CDT, was "in Evanston," which makes more sense when you remember that Facebook used to preface every post with "Nerdly McSnood is...". (This was before Facebook allowed public posts, and there doesn't seem to be any way to change the post's privacy, so if you're not Facebook friends with me you probably can't see it.)
Anyway, just a bit of trivia. And a little horrifying that 10 years have gone by.