Yes, Facebook users did have that power. Whether or not they took advantage of it is another story, but if all Facebook's users decided to leave without a TOS change I bet they would have got the changes because there is no FB without users -- same with governments. And there is a mountain of difference between having motivation to try to effect TOS changes, versus a human condition prevalent with graphic images of your neighbors being beaten and shot in the streets.

So, yes, I do believe the people have the power to overthrow the Ayatollah (or any other govt. for that matter) if they are organized enough. Unfortunately, I don't see that large undertaking helping even if it were to happen because the Iranian people largely want a theocratic government, which to me will be inherently dictatorial. It comes down to this: the Internet is inherently about connections -- connecting computers, which by extension connect people. It's not social networks themselves that provide the magic, they're just vehicles riding on top of that fundamental connection potency; that's where their success has come from. When you want to give people power you let them connect, communicate and organize. When you want to weaken them, you isolate them. It's that simple.