The card processor, Global Payments, claims that fewer than 1.5 million cards in North America were involved in the breach. They also state that cardholder name, address and Social Security numbers were not compromised. Global Payments: less than 1.5M impacted by breach - Yahoo! Finance
The breaches seem to be happening with some regularity but apparently are not hurting the credit card companies enough to consider transitioning to the chip and PIN system used in Europe. Global Payments will reach some type of settlement with MasterCard and VISA and the consumers affected by the breach will not be compensated at all.