because the trend appears to be (as an outsider) that what matters is not revenue or chance of profit, it's the amount of users a site can acquire. File sharing

because the trend appears to be (as an outsider) that what matters is not revenue or chance of profit, it's the amount of users a site can acquire. File sharing is easy to do (arguably hard to perfect) and a good file sharing site will get a lot of users. Maybe they're funded in the hopes of a buyout? Dropbox validated the idea that file sharing can get high valuations...