I'm not much a fan of Facebook, but it's only fair to give them credit where credit is due - things like Cassandra, HHVM/Hack, and React are all pretty important technologies, and their datacenter needs mean they've built an internal competency for hardware, too.

I don't think this move makes obvious sense, but Facebook The Company (as opposed to Facebook The Product) is more than just an RSS feed of lolcats.