Yelp was founded in 2004 by two former PayPal employees and has since expanded to over 40 states and several countries. It is a social networking site that allows users to review local businesses in their area across various categories. Members have profiles and can connect with friends while building a trusted community through written reviews, ratings, and discussions. While some businesses have accused Yelp of extortion related to advertising, the site has become a popular resource for customers to research local options.