As Krista so eloquently wrote it:
Via We want you: Automattic is hiring in 2013 — Blog — WordPress.com.
If you weren’t sure why I work at Automattic, here’s why. And if you weren’t sure why you should be using WordPress, here’s why too. Two birds, one stone thrown. :)
WordPress is the antidote to walled gardens.
Source: Tumblr Support in WordPress — Matt Mullenweg.