This is the company that bragged about having 18,000 classes for their iOS app [1] and having to patch the Dalvik Virtual Machine to support new features in their Android app [2]; they are not infallible.
[1] http://quellish.tumblr.com/post/126712999812/how-on-earth-th...
[2] https://www.facebook.com/notes/facebook-engineering/under-th...