Technically, yes. There are generally no geographical restrictions to where you shout about ProfitDuel (unless there’s anything country-specific around companies operating in this sector, for example).
However, it needs to be remembered that to use ProfitDuel members need to have a SSN and be located in one of the states we’re currently active in - they don’t need to live in that state, but they need to be in it.
They could of course be made aware of ProfitDuel while they’re vacationing in Europe, but to use it they need to be back in the U.S.