When the revolution comes, someone's always ready to tell you how Facebook and Twitter are powering history.
The problem is that while they're still standing, governments can snuff out Facebook and Twitter whenever they like. All they need do is flip the "off" switch on the servers, routers, and wireless equipment used by local service providers.
Just ask Bill Gates.
When US TV anchor Katie Couric asked the Microsoft co-founder and chairman if he was surprised that Egyptian president Hosni Mubarak could take the unprecedented step of killing the entire Egyptian internet, Gates responded with an emphatic: "no".
Sometimes, he knows what he's talking about.
"It's not that hard to shut the Internet down if you have military power where you can tell people that's what's going to happen," Gates said. "Whenever you do something extraordinary like that you're sort of showing people you're afraid of the truth getting out, so it's a very difficult tactic, but certainly it can be shut off."
