XAuthorize.net sold a similar product for a number of years. I'd think that (not having done more than skim the patent) it would count as prior art in the event

XAuthorize.net sold a similar product for a number of years. I'd think that (not having done more than skim the patent) it would count as prior art in the event MSFT wanted to protect that IP -- assuming that it could pass the non-obviousness test.