One of the main threats to US-friendly online poker room based from outside the US is the inevitable path towards regulation by more and more states. As of today, already 3 states have regulated online poker gameplay and more are expected to follow suit. The Poker Player's Alliance (PPA) has predicted that California, the state which holds 12% of the entire US population, would move towards regulation and legalization of poker by 2014.
This would mean a slow but steady decrease in activity, customers and revenues for offshore online poker sites. These companies proactively looking for ways to salvage their business and they found it by diversifying their operations model. These sites now offer and complement their product line with online sports betting, live-betting, exchange betting, horse racing and even casino gaming.
Sports betting is of course the main focus of business for US-friendly gambling companies based outside the US. Right now sports betting is legal in but 2 of the 51 states and with the insatiable appetite for sports wagering that Americans have, this market is prime real estate for these companies. Offshore sports books offer US players the chance to shop for better lines and odds, which Nevada neglects since they all offer pretty much the same lines and odds throughout the state.
Right now international sports books pretty much have a monopoly on the sports wagering market in the United States and things will not likely change unless New Jersey manages to win their lawsuit against the major sports leagues and the USDOJ. And even so, it would take years until the scenario changes enough for these companies to give up on US traffic.