Your birthday is the day that you’re reminded of any message boards you joined in the last twenty years:
And that CVS thinks you’re beautiful. Aw, shucks.
Also, it’s a reminder that Google KNOWS you.
…which, I have to admit, is pretty cool.
It’s also the one day of the year everyone remembers you’re on Facebook, and you feel guilty about all the people you didn’t wish a happy birthday back to in the last year.