I agree with a lot of the reasons people give for not using facebook, most substantially the privacy concerns. However, I think the 'someone might read your old status messages and judge you for it' [1] idea is a ridiculous way to live your life.

If people are going to judge you on a random message you wrote five years ago, that's their fault, not yours. I think Randall Monroe explains it best: http://xkcd.com/137/ .

[1] (FTA "A vindictive ex-partner, or a workplace rival, or a health insurer, or a political opponent, may selectively expose information to your detriment – powerfully re-framing your identity in a way you would consider dishonest.")