You can use Visa to buy porn (including on eBay), but not PayPal. Strange, isn't it? I guess because it's so much harder to get a Visa merchant account, with more hoops to jump through, not to mention higher fees, that they're more willing to take the risk of "adult" transactions than with "third party" billers like PayPal. That's the difference. That's why I think eventually we'll be able to buy some items with PayPal here at Rosity, while some items will be credit cards only.