The idea that social media are defined simply by their ability to bring people together has been seen as too broad, as this would suggest that fundamentally different technologies like the telegraph and telephone are also social media. The terminology is unclear, with some early researchers referring to social media as social networks or social networking services in the mid 2000s. A more recent paper from 2015 reviewed the prominent literature in the area and identified four common features unique to then-current social media services:
Social media might can also function as a supportive system for adolescents' health, because by using social media, adolescents are able to mobilize around health issues that they themselves deem relevant. For example, in a clinical study among adolescent patients undergoing treatment for obesity, the participants' expressed that through social media, they could find personalized weight-loss content as well as social support among other adolescents with obesity The same authors also found that as with other types of online information, the adolescents need to possess necessary skills to evaluate and identify reliable health information, competencies commonly known as health literacy.
Periscope is a live video streaming mobile app that was developed by Joe Bernstein and Kayvon Beykpour. The two started the company in February 2014 and later sold it to Twitter for $100 million in March 2015. Four months after its March 2015 relaunch, Periscope said that it had surpassed 10 million accounts and in December the same year, Apple announced Periscope as the app of the year.
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.