YouTube, as with many other popular websites, is blocked in many countries of the world. The reasons vary, but they usually have something to do with governments wanting to keep certain videos from being available to their people.
One of these countries is Pakistan, where YouTube was banned over, what else, the Innocence of the Muslims video that has caused plenty of protests and violence in many parts of the world, including Pakistan.
Since the ban though, Pakistan has been working on a smarter block, one that would make most of the content on YouTube available while still keeping out the objectionable content.
So, when government experts were ready to test this new block, the ban on YouTube was lifted. For a whole three minutes, since that's how much it took the experts to realize that their smarter block wasn't working, so they blocked YouTube all over again.
Naturally, this sparked a new wave of criticism from those opposing the ban, though that's probably not going to change the government's mind any time soon.