Online porn has been around long enough now that I think if Visa and Mastercard were going to stop processing for porn sites they would already have stopped by now.
Also, I think there is less fraud in the porn industry now then there was like 3-4 years ago, and as the years go by there will be even less fraud. This industry used to be like the old wild west and the gold rush days, but now its turning into a very well established industry with well established companies.
There probably was a time where Visa and Mastercard considered getting out of the porn processing industry. They probably thought "well, we can call it quits now and be done with porn processing, or we can stay in this and find new and innovative ways to reduce fraud and chargebacks." I think they have chosen to stay in the game for the long haul, and they are continually working on new ways to reduce fraud and chargebacks.
Fraud and chargebacks are the porn industry's biggest problem. Any good businessman (or woman) knows that where there are problems there are opportunities.
Visa and Mastercard aren't stupid, they know there's a HUGE opportunity to make shitloads of money in the online porn industry, and they want every fucking cent of it. Its good to see that they have stuck it out this long, and they didn't pussy out like shitty American Express.
