AOL had this first (Score 2, Interesting)

AOL already has pay-per-call ads and has had them for a few months. AOL uses Ingenio's PPC call system and that is the same system Yahoo PPC ads are based on. They use a mechanism where a unique 800 number is generated that will hook you up with the ad your trying to reach (even if the buisness didn't already have an 800 number). Googles approach on the other hand is very flawed. As several other posters already pointed out you can simply put anyones phone number in the phone field to make crank calls on the advertisers dime all day long!