Yelp could very well be the source of a new breed of Google bombs -- like the one seen on Google Maps when searching for "Microsoft". How is this possible? Well, "Sara B" decided to upload an anti-Windows image along with her review of the company -- it so happens she reviewed the #1 ranking result on Google Maps for the term "Microsoft". This is a problem because images from Yelp appear in the organic search results on Google Maps.
Intentional or not, this could be a serious problem just waiting to happen. From what I can tell, nothing can prevent people from uploading any image for any company they want. I'm not certain how easy this is to actually exploit, or how long the image would last if someone was successful -- users can easily report inappropriate photos through the Google Maps interface.