Yeah but in PayPal's case, they were all MasterCard numbers. And keep in mind that since one of the primary uses was to be able to Pay secretly with PayPal on a site that doesn't support it, the number would have to validate through the merchant's existing CC system. MasterCard was clearly on board with the process.
> MasterCard was clearly on board with the process.
They might have been when it started, but clearly something changed. If it was desirable, the moment PayPal decided not to continue, MasterCard would have started looking for alternatives. Since they didn't (and haven't), its pretty reasonable to assume they decided intentionally not to pursue it.
The two other functioning alternatives listed in this thread, getfinal.com and privacy.com, both Visa. Kinda says it all there.
My mastercard had the same feature sometime along the way that they advertised strongly to me on the website. I think I might have used it once, but it was too much of a hassle to log in to my account, generate the number, go back to the website that I was purchasing from, etc.