Please don't ask me why, but I'm going to go out on a limb and guess that one of the people who "invented" this system at Twitter is a Xoogler.
But, Google really has no right to whine about this. They make an explicit tradeoff: they manage to stay 3-5 years ahead of the curve of everyone else by not open sourcing their impressive libraries and infrastructure. But the corollary of that is that there's no place to whine "we got there first!" when someone else produces an implementation of X.