Oh, really? Does that mean that, if you owe $1000 in tax, you can give it to a charity of your choice, rather than the government? That sounds like a pretty big advantage.
In canada, anyway, you have a limit as to how much you can donate and you receive tax credits in return. It's not 1:1 though, so it's not as if I can just donate my taxes to a charity rather than the government.