I just had the following paid sign up appear in my account history:

#2155557 Paid Signup: Yahoo Success Center 14.00 Credits 04/28/2011 Credit Hold until 05-15-2011

I never gave out my credit card for anything but from what I am reading this is a free trial offer that you get charged for after the trial period. I really don't remember where this came from. How could I be charged if I never gave any credit card info?