I suspect even that signal is not trustworthy. Given that its not 100%, what fraction of the 900+ million Facebook users are actually users? Twitter seemed to b

I suspect even that signal is not trustworthy. Given that its not 100%, what fraction of the 900+ million Facebook users are actually users? Twitter seemed to be totally plagued with that at one point anyway. What's the grey area look like? What's the chance of falsely identifying a real user as a fake one? Rhetorical question. Not sure FB could even answer them accurately.