I make it clear a couple of times that there are duplicate users in those numbers. Additionally, I divide the total user count into FB's unique count, which giv

I make it clear a couple of times that there are duplicate users in those numbers. Additionally, I divide the total user count into FB's unique count, which gives you the number two. So, of the four Apps Facebook is giving numbers for... users on average are using two. Google has a dozen Apps in the store, and there is some overlap as well. This is the state of the art: one function per App. We'll see a LOT more of this over time. In fact, Google just made Docs into a couple of different Apps -- instead of just one with sheets, docs, presentations, etc.