See the recent kerfuffle about online gambling domain name seizures. If something is deemed illegal for US consumers, the DOJ works pretty hard to shut it down

See the recent kerfuffle about online gambling domain name seizures. If something is deemed illegal for US consumers, the DOJ works pretty hard to shut it down regardless of jurisdiction - although if I recall correctly, one of the triggers for seizure in the online gambling case was that the sites were clearly marketed as catering for the US consumer.