Well, they continue to add users (albeit more slowly), and the world population is increasing, so I don't see any evidence that they won't add any new users. T

Well, they continue to add users (albeit more slowly), and the world population is increasing, so I don't see any evidence that they won't add any new users. They actually don't even have 20% penetration of "everyone" by monthly active users, and I'd argue Facebook is on its way to being as ubiquitous as email.