It’s not just MathOverflow’s birthday. It also got its own article on the Atlantic’s website. It probably won’t tell you much you don’t know if you’re a user of the site (and I hope you all are), but hey, there’s no such thing as bad publicity, right?
I’m also fairly amused that they managed to actually come up a photo of overflowing math to illustrate the article. It’s much more illustrative than any of MO’s official graphics.