Woah, I think "being dumb" describes it better 
Perhaps I used the wrong word for the same thing? I am sure that each state has a sales tax of some kind which works in much the same way, albeit at a lower percentage than is common in Europe.
It has to do with the fact that each state in the US is in some sense independent, and that the Constitution grants the federal government the power to regulate interstate commerce. The state of New York, say, does not have the authority to impose a tax on a company in New Jersey unless that company has done something that makes it subject to the jurisdiction of New York (such as having a New York office). Otherwise New York would be violating the rights of the New Jersey company, or attempting to regulate interstate commerce, which is a power reserved to the federal government. Some argue that connecting to the internet alone is a sufficient presence in a state for taxes to be collected, but that argument has not won out. A strong argument against that is that any company connected to the internet would have to be prepared to levy sales taxes based on the local laws, which can vary not only from state to state, but city to city!
New York, has tried to get around this by levying the tax directly on its citizens, rather than on the out-of-state company. You are supposed to list, on your NY State Income Tax form, all out of state purchases and send in the required tax yourself. So even though Amazon doesn't collect it, a New Yorker is in principal not off the hook. I'd like to know if anyone has ever done that.
