The eClick Performance blog has a story about Yahoo Local getting hit with tons of affiliate spam. Yahoo Local is currently the only local search of the big three (Google, Yahoo, and MSN) that seemingly allows anyone to edit and change any listing (Google and MSN both require phone or mail verification of ownership). Now, I am pretty sure you can't just put any ol link in for a business, every listing would be pointing to porn I am sure. The affiliate marketers have found a way to game the system, though. They send the link to a redirect page that gives them a "sale" in the affiliate program, but still (eventually) resolves to the correct page. The worst part for business owners is that it appears the only way to verify your listing (and thereby lock it down from edits) is to sign up with Yahoo Local advertising.
This is one of the major problems with yahoo today, they should filter out the spam to maintain the quality.