Fenris is correct. This is so not happening in its present form. The EU are going to make complete fools of themselves by attempting to do this unilaterally.
First, from a practical standpoint, any country can declare a tax on anything. Albania can declare a tax on land transfers in New Jersey if it likes. However, if the country has got no leverage to collect it, the tax is meaningless. "I can call spirits from the vasty deep! " “Why so can I, or so can any man; But will they come when you do call for them?”
Second, no other country is going to act as the EU’s tax collector. For one thing, there is way too much precedent – even in the EU – for ignoring another country’s law which you happen to dislike. Many countries, for example, have laws specifically prohibiting the enforcement of U.S. anti-trust judgements.
Third, as for the U.S., there is no conceivable possibility that any state of the federal government would – or could – pass a law imposing a European tax on digital Internet sales to Europe. Under current U.S. constitutional law, a state is constitutionally prohibited from forcing an out-of-state company to collect sales taxes on sales into the state. The U.S. federal government is just not going to impose a national “out-of-country” sales tax for the benefit of foreign governments.
Fourth, and somewhat more philosophically, the EU is trying to impose its “consumer-centered” model of Internet transaction. The EU pushes the theory that the locus of the transaction is where the customer resides, rather than where the company is located. Therefore, the consumer’s national law, taxes, etc. apply to the transaction.
Obviously, there is some debate about this. The U.S. has, so far, mostly followed a “seller-centered” model.
This tax will only impact companies that the EU can reach. If you are really big and have offices in Europe, you will probably have to comply with EU law. If you are shipping tangible products, you’ll probably also have to comply or, more likely, the EU will simply impose a customs duty. However, if you are an Internet company based somewhere other than the EU delivering digital content, you’re home free.
BTW, the Foreign Sales Corporation problem that LC mentioned is a completely different problem. The WTO found FSC’s discriminatory because they effectively made income earned from foreign sales tax free (more or less). Foreign digital sales, however, are taxed exactly the same as out-of-state U.S. domestic sales.