Source: http://feeds.gawker.com/~r/lifehacker/full/~3/378045962/phonespamfilter-identifies-telemarketers
Receiving frequent phone calls from a number you don't recognize? If you've ruled out the possibility that it's your Venezuelan stalker, turn to the PhoneSpamFilter web site to figure out exactly who it is that's calling you. Users submit complaints about numbers that have called them at PhoneSpamFilter, and you can see if the same number that's been bugging you appears there. Just this week a mystery number kept calling my wife's cellphone and leaving cryptic messages about cars and extended warranties. A search of the PhoneSpamFilter database for that number yielded complaints from other people about automobile-related telemarketing calls originating from that number. Mystery solved. If you don't find anything with a search at PhoneSpamFilter, check out CallerComplaints.