Is there a more specific reason you want to know. For online payments use a low limit card or much better a one use card for unknown or untrusted websites. Big well known trusted businesses should be ok. But if you want to do business with a smaller company you have no clue of try a one use card just in case.
I have no intention of purchasing from them ... neither did the other people who had charges from these sites. They had never heard of these places until the charges appeared on their accounts.
I'm curious to know how (or where) they are getting the account numbers to use for fraudulent charges. Some implications have been that a common thread is the use of PayPal, amazon and ebay. I would like more clarification if I can find it so I know whether to alert my family members.