Yelp, one of the best known online review sites, is no stranger to upset business owners. Founded in 2004, Yelp provides crowd-sourced reviews for local businesses. This format gained them a large community of Yelpers and a reputation as a quick, easy way to research purchasing decisions. Despite a generally positive response to Yelp, there have been numerous controversies over the years. These mainly revolve around how to determine what is and isn’t a valid review.