Having > 500 million users. That's a lot of different kinds of people to make happy. That's a huge ship to turn around. That's a huge amount of surface area to

Having > 500 million users. That's a lot of different kinds of people to make happy. That's a huge ship to turn around. That's a huge amount of surface area to be spread over. Having to serve the lowest common denominator for that many users in a community oriented platform is going to leave a lot of needs unserved, or served poorly. It leaves plenty of holes for a disruptive company with nothing to lose to show up and do something interesting. The converse strength they can leverage, though, is also their huge numbers: users, engineering staff, sales people, technology partners. If they realize the power of a disruptive idea just early enough, they have the resources and culture necessary to build and scale it in what may as well be an instant fashion, since they can drop it on millions of users at once.