StumbleUpon is a discovery engine that finds and recommends content for its users. Come June 30, 2018, it will be moving to Mix. More than 25 million people use StumbleUpon for entertainment and information. In addition, more than 80,000 publishers, brands, and other marketers have used StumbleUpon’s Paid Discovery platform to promote their businesses. StumbleUpon was owned by eBay from May 2007 to April 2009, when Garrett Camp, Geoff Smith and several investors bought it back. It is now an independent, investor-backed startup once again.
On social media, consumers are exposed to purchasing practices though peer sent, written messages. Learning through social media includes strategies such as "modeling, reinforcement, and social interaction mechanisms" all at the same time. A study, that focused on peer communication through social media, has revealed that communication between peers through social media is positively related to purchase intentions in a couple ways. First, is a direct impact through conformity. Second, is an indirect impact by stressing product engagement. Lastly, from this study, we learned that consumer-related communication between peers on social media has a positive relationship with product engagement. 
Networks formed through social media change the way groups of people interact and communicate. They "introduce substantial and pervasive changes to communication between organizations, communities, and individuals." These changes are the focus of the emerging fields of technoself studies. Social media differ from paper-based media (e.g., magazines and newspapers) and traditional electronic media such as TV broadcasting in many ways, including quality, reach, frequency, interactivity, usability, immediacy, and performance. Social media outlets operate in a dialogic transmission system (many sources to many receivers). This is in contrast to traditional media which operates under a monologic transmission model (one source to many receivers), such as a newspaper which is delivered to many subscribers, or a radio station which broadcasts the same programs to an entire city. Some of the most popular social media websites are Facebook (and its associated Facebook Messenger), Instagram, WhatsApp, Google+, Myspace, LinkedIn, Pinterest, Snapchat, Tumblr, Twitter, Viber, VK, WeChat, Weibo, Baidu Tieba, and Wikia. These social media websites have more than 100,000,000 registered users.