This is clearly a scam site. Its alleged function is to let you type in a phone number if you get a junk call and find out whose it is. However, I tried putting in my own home number, and then the number of several friends of mine. They always come up with a set of a few random complaints claiming "I received a call on my cell phone from this number" or "Didn't leave a message when I phoned back - why do these scammers do this??". The giveaway was that all complaints had today's date, and a time IN THE FUTURE (about 22:00 tonight, although I checked at 14:00).

Since I don't make junk calls, and wasn't even at home when I tested this (and got today's date as the date of the alleged "junk call"), it's clearly a scam. What they get out of it, I'm not sure!