Ever wondered who has called you? Ever asked, "Who's Number Is This?"? The number is not registered on your phone list and you don't have any single idea who was the caller. You are afraid to call back because of the anonymity of the caller. Ever also tired of getting calls from telemarketers who bother you every single day? Well, here's the solution for you: at whosnumberisthat.com, you can obtain information from your anonymous calls, who they are, their provider, their address and a lot more. They also have features like No Call list information where you can exclude yourself from the telemarketers list thus, relieves you from those unwanted calls.