It will take several years for his patent to make its way through the system. In the meantime, software patents will be abolished.</wishful thinking> He could

It will take several years for his patent to make its way through the system. In the meantime, software patents will be abolished.</wishful thinking> He could reasonably claim infringement if he can produce documentation saying that he came up with the idea before your service went live. If he is a standard patent troll, he will probably request a license fee that's low enough to be tempting given the alternative (a potentially expensive legal battle where you have to disrupt your operations to gather proof of prior art and focus on this rather than on your business). Unless you're willing to fight him just on principle, it may end up being cheaper for you to pay his fee and call it a day.