Social media are computer-mediated technologies that facilitate the creation and sharing of information, ideas, career interests and other forms of expression via virtual communities and networks. The variety of stand-alone and built-in social media services currently available introduces challenges of definition; however, there are some common features:
Users create service-specific profiles for the website or app that are designed and maintained by the social media organization.
Social media facilitate the development of online social networks by connecting a user's profile with those of other individuals or groups.
Users typically access social media services via web-based technologies on desktop, computers, and laptops, or download services that offer social media functionality to their mobile devices (e.g., smartphones and tablet computers). When engaging with these services, users can create highly interactive platforms through which individuals, communities, and organizations can share, co-create, discuss, and modify user-generated content or pre-made content posted online. They "introduce substantial and pervasive changes to communication between organizations, communities, and individuals." Social media changes the way individuals and large organizations communicate. These changes are the focus of the emerging fields of technoself studies. Social media differ from paper-based media (e.g., magazines and newspapers) to 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 Baidu Tieba, Facebook (and its associated Facebook Messenger), Google+, Myspace, Instagram, LinkedIn, Pinterest, Snapchat, Tumblr, Twitter, Viber, VK, WeChat, Weibo, WhatsApp, and Wikia. These social media websites have more than 100,000,000 registered users.
In the United States, a 2015 survey reported that 71 percent of teenagers have a Facebook account. Over 60% of 13 to 17-year-olds have at least one profile on social media, with many spending more than two hours per day on social networking sites. According to Nielsen, Internet users continue to spend more time on social media sites than on any other type of site. At the same time, the total time spent on social media sites in the U.S. across PCs as well as on mobile devices increased by 99 percent to 121 billion minutes in July 2012, compared to 66 billion minutes in July 2011. For content contributors, the benefits of participating in social media have gone beyond simply social sharing to building a reputation and bringing in career opportunities and monetary income.
Observers have noted a range of positive and negative impacts of social media use. Social media can help to improve an individual's sense of connectedness with real or online communities, and social media can be an effective communication (or marketing) tool for corporations, entrepreneurs, nonprofit organizations, advocacy groups, political parties, and governments. At the same time, concerns have been raised about possible links between heavy social media use and depression, and even the issues of cyberbullying, online harassment and "trolling". Currently, about half of young adults have been cyberbullied, and of those, 20% said that they have been cyberbullied regularly. Another survey in the U.S. applied the Precaution Process Adoption Model to cyberbullying on Facebook among 7th grade students. According to this study, 69% of 7th grade students claim to have experienced cyberbullying, and they also said that it was worse than face-to-face bullying. Both the bully and the victim are negatively affected, and the intensity, duration, and frequency of bullying are the three aspects that increase the negative effects on both of them
Social media has a history dating back to the 1970s.ARPANET, which first came online in 1969, had by the late 1970s developed a rich cultural exchange of non-government/business ideas and communication, as clearly evidenced by ARPANET#Rules and etiquette's "A 1982 handbook on computing at MIT's AI Lab stated regarding network etiquette," and fully met the current definition of the term "social media" found in this article. Usenet, which arrived in 1979, was beat by a precursor of the electronic bulletin board system (BBS) known as Community Memory in 1973. True electronic bulletin board systems arrived with the Computer Bulletin Board System in Chicago, which first came online on 16 February 1978. Before long, most major cities had more than one BBS running on TRS-80, Apple II, Atari, IBM PC, Commodore 64, Sinclair, and similar personal computers.
The IBM PC was introduced in 1981, and subsequent models of both Mac computers and PCs were used throughout the 1980s. Multiple modems, followed by specialized telecommunication hardware, allowed many users to be online simultaneously. Compuserve, Prodigy and AOL were three of the largest BBS companies and were the first to migrate to the Internet in the 1990s. Between the mid-1980s and the mid-1990s, BBSes numbered in the tens of thousands in North America alone. Message forums (a specific structure of social media) arose with the BBS phenomenon throughout the 1980s and early 1990s. When the Internet proliferated in the mid-1990s, message forums migrated online, becoming Internet forums, primarily due to cheaper per-person access as well as the ability to handle far more people simultaneously than telco modem banks.