“ The next email had just a number (‘37’) in the subject - and no message text. What a weird form of spam, I thought. Why would anyone be motivated to just send a number? I searched for the user’s email address to see what else had been sent. Interesting. Lots of numbers: 33, 53, and then a clue: ‘61, getting a bit heavy, aren’t we?’ ”
Marissa Mayer, theOfficial Google Blog: What comes next in this series? 13, 33, 53, 61, 37, 28…

Somebody deserves some credit for the continued simplicity of the Google homepage.