Does nothing as far as I can determine.

A year ago I was told that lifelock could do nothing when I was notified by the IRS that someone had already filed taxes for me. Therefore I had to notify and change all accounts etc. Last month someone used my credit card number for 2 transactions either online or phone except that there was not a phone number listed for the one merchant. I do not have any idea what exactly it is that lifelock does.