Target, reassuring "guests" whose credit and debit card information was compromised in a December hack on the retail chain. - 

Millions of Americans have had credit card and debit card information stolen by hackers at big retailers like Target and Neiman Marcus.

Bob Sullivan, consumer advocate and investigative journalist at, says “this is going to be the most important credit card hack ever.”

Need more advice? Sullivan wrote more tips about protecting yourself on his website