http://www.renesys.com/blog/2008/02/pak ... tube.shtml
For those of you unfamiliar with such horrid technojargon, this is a basic rundown of what happened.
Pakistan took YouTube's address (not http://www.youtube.com but something more like your IP Address). Then they went to their routers. Now, the way routers work is they go, and they get data from you saying go to place X, and then they go and they look at this table (a chart, of sorts) that they have. Then they go and they choose the fastest route to get you to place X, in this case youtube. And so what Pakistan did was they set up a fake site, and manually set their routers to read a request for youtube, and then say that the route to their fake site was the fastest way to get to youtube. Pretty clever, eh? No, not really... See, all the routers out there go and check the other routers that they're connected to check their tables and update their own. So, all the routers connected to Pakistans routers outside of Pakistan went and said "Hey! Look at this super fast connection to youtube!", and then all the routers connected to those routers saw that, and so on. This, in effect, brought down youtube for two hours...
