the youtube comparison is spot on. too big to fail. and while we're at it, the fact that most of all big websites are from the states has for a significant part to do with the american way of consumer marketing and what is considered lawful over there - namely the lax handling of copyright issues (fair use), a loose opt-out system that prefers the marketers and barely existing or enforced privacy laws.
it seems to be gererally accepted that you as the user have to take action to prevent your commercial exploitation by the internet firms. so you have to ask youtube or pinterest to get your stuff removed, unthinkable in many other legal systems. these are the conditions that put american websites ahead and make them big in the first place.
imagine if they would have to ask you first. imagine if they would have to check every user submission for copyright issues beforehand. instead they push aside liability.
an opt-in principle where people have to give permission is common legal practice in any other branch. except for the internet, especially american internet..