SparkPeople is a unique, free social networking site for people online dieters. In fact, comScore reported that it has surpassed Weight Watchers as America’s largest diet and fitness Web site by unique visitors. SparkPeople has 13 million members. The members come together around diet and fitness challenges, common interests and activities, message boards, homepages, email and InMail. SparkPeople’s iPhone app was rated number one by Duke University among diet and fitness apps.