A Yelp user has a unique Yelp ID, first name, last name, gender, birthdate, birthplace, age, email, a profile picture, and a list of friend IDs. Yelp users can be complimented by their friends. A Yelp user can rate any business on a scale of 1-5 and provide reviews. A user has an "Activity Wall" where the 10 most recent Yelp reviews by the user's friends are posted on the wall when the user “follows” their friend’s activities. In addition, the user can check in to a particular business.