social media, a form of mass media communications on the Internet (such as on websites for social networking and microblogging) through which users share information, ideas, personal messages, and other content (such as videos). Social networking and social media are overlapping concepts, but social networking is usually understood as users building communities among themselves while social media is more about using social networking sites and related platforms to build an audience.

The earliest forms of social media appeared almost as soon as technology could support them. E-mail and chat programs debuted in the early 1970s, but persistent communities did not surface until the creation of the discussion group network USENET in 1979. USENET allowed users to post and receive messages within subject areas called newsgroups. USENET and other discussion forums, such as privately hosted bulletin board systems (BBSs), enabled individuals to interact, but each was essentially a closed system. With the release in 1993 of the Mosaic web browser, those systems were joined with an easy-to-use graphical interface. The architecture of the World Wide Web made it possible to navigate from one site to another with a click, and faster Internet connections allowed for more multimedia content than could be found in the text-heavy newsgroups.

The first companies to create social networks based on web technology were Classmates.com and SixDegrees.com. Classmates.com, founded in 1995, used an aggressive pop-up advertising campaign to draw web surfers to its site. It based its social network on the existing connection between members of high-school and college graduating classes, armed service branches, and workplaces. SixDegrees.com was the first true social networking site. It was launched in 1997 with most of the features that would come to characterize such sites: members could create profiles for themselves, maintain lists of friends, and contact one another through the site’s private messaging system. SixDegrees.com claimed to have attracted more than three million users by 2000, but it failed to translate those numbers into revenue and collapsed with countless other dot-coms when the “bubble” burst that year for shares of e-commerce companies.

More From Britannica

media convergence: Social media

Nevertheless, social media sites became popular in the early 21st century. Social networks such as Friendster and MySpace emerged that allowed family members, friends, and acquaintances to connect online. Those two sites were eventually supplanted by Facebook, which became one of the world’s most popular social media sites with billions of users worldwide. Other forms of social media emerged for the sharing of specific types of content. For example, YouTube allows users to share videos, and TikTok is specifically designed for the sharing of short videos. LinkedIn emphasizes a user’s professional connections, where users create pages similar in structure to résumés.

Concerns over the possible negative effects of social media are also growing in tandem with the burgeoning technology. For example, some observers suggest that social media sites spur greater schadenfreude—the emotional experience of pleasure in response to another’s misfortune—perhaps as a result of the dehumanization that occurs when interacting through screens on computers and mobile devices. Some studies also suggest a strong tie between heavy social media use and increased depression, anxiety, loneliness, suicidal tendencies, and feelings of inadequacy. During his second tenure as U.S. surgeon general, Vivek Murthy raised concerns about social media’s impact on children and in 2024 he suggested mandated warning labels on social media sites.