The libertarian answer is "to let the market decide" and walk with their pocketbook / talk with their wallet. That is all fine in theory but the theory doesn't address what happens when there is only a single dominant player. For example, if I "walk away with my wallet" on my cable tv provider, i'm done -- there is only one provider.
Facebook and your cable company are similar in that they both offer a compelling (for some people, at least), yet unessential product.
in these situations, you vote with your wallet by no longer using the service. there are issues with the libertarian "vote with your wallet" theory, but this is not one of them.
there might be some diehard libertarians that disagree with me, but I think it's pretty obvious that the theory can't work when a company has a monopoly on a truly essential product.
I live in a place (Canada) where even some non-essential products are monopolized not by private companies, but by the government. In fact, the only monopolies of which I am aware are created and mandated by government.
