Facebook is infrastructure. It provides the connections out to your personal network. Facebook's staying power comes from its ability to say "This is the best way to communicate with your personal network at any time". "File hosting" is just one subelement of that, because one of the things that you may want to share is a file.
Couldn't the whole internet be generalized as "file hosting with a bunch of links"? A "file host" is a company whose primary purpose is for you to upload a file and give the link to someone else; they're a middleman that exists only because a more convenient/direct means of distribution to the intended network isn't available. This does not make the company nearly loud enough to establish its own identity/user base.
Facebook has always been its own repository of people intelligence. It was never just an "upload your photos here". Such platforms, like Photobucket or Imgur, sometimes prosper for a while, until the communication channels that reach the intended audience directly offer something easier. (imgur is going down now as reddit introduced its own image host last year)
Yes, though it's 1) the largest such service with 2) some very sticky features.
(Not that I use it.)
Realise that the flipside of such services is their real customers -- the adverts side. For online advertising, the two largest agencies claim over 60% of the market, and are named "Google" and "Facebook".
Everyone else is an also-ran. Which for any ads purchaser means "a lot more work for a lot less reach".
Was actually just trying to create a counterpoint to the claim that file hosting services don't make money. Facebook is a hosting service for pictures and comments, and it makes money.
