FILE - In this Tuesday, Jan. 7, 2014, file photo, Yahoo president and CEO Marissa Mayer speaks during a keynote address at the International Consumer Electronics Show, in Las Vegas. Yahoo said Thursday, Jan. 30, 2014, that usernames and passwords of its email customers have been stolen and used to access accounts, but the company isn't saying how many accounts have been affected. (AP Photo/Julie Jacobson, File)