MrHard - 9:05 am on Mar 2, 2010 (gmt 0)
The scary part about Yelp is that you cant opt out as a merchant. If someone has an axe to grind it stays and shows up in Google. From there you have to try to get more positive reviews then bad, maybe list Yelp on your site or give in and pay.
We all know that a satisfied customer is less likely to review then a disgruntled one, at least the ones I've seen. A built in income maker for yelp.