An anonymous reader writes "You're doing something interesting. The phone rings. You get up, pick up the phone, and hear only silence. It could be a slasher waiting outside your house, but it's probably an errant computer at a telemarketer. This article describes how some are fighting back by setting up websites to track the worst telemarketers by their caller ids. The article mentions whocalled.us (one of the funnier urls I've ever seen), 800notes.com and numberzoom.com . One intrepid guy is even writing a program to check these sites when the call comes in before ringing the phone."