The Internet began as a project of the U.S. Department of Defense in the 1960s to create a comprehensive, indestructible computer network that could communicate even when under enemy attack. An internetwork (a network of networks) called ARPANET was created to meet this goal, although the networks were still not linked worldwide. Eventually military and defense contractors, universities, science agencies, and other organizations were allowed to connect to this internetwork. In 1983 a new protocol called Transmission Control Protocol/Internet Protocol (TCP/IP) was integrated into ARPANET, making the internetwork widely accessible. Many Internet historians cite ARPANET’s switching over to TCP/IP as the event that marked the birth of the Internet.

In the early 1980s breakthroughs in integrated circuit technology made personal computers more affordable, and commercial Internet services and applications became popular. But online information was difficult to access because of poor computer interfaces. In 1989 a physicist named Tim Berners-Lee developed a way to organize information in a more logical fashion by using hypertext to link portions of documents to one another. He called it the World Wide Web.

It took another four years before Mosaic, the first Internet browser, became available. Mosaic, which used a “point-and-click” interface, made it much easier to access, retrieve, and display resources on the Internet. In 1994 Netscape Communications Corp. was founded to further develop the Mosaic browser. Soon thereafter the Microsoft Corporation developed its Internet Explorer browser (which was initially based on Mosaic), and the Internet expanded rapidly.

The Internet quickly became a go-to resource for information, but companies also began to see dollar signs in the Internet. In 1995 Amazon.com went online and many companies began developing an online presence. Today Amazon.com is the world’s largest online retailer. Internet companies grew quickly, and many “went public” via initial public stock offerings to raise money to expand their businesses. Today all major “brick-and-mortar” retailers have Web sites, but many companies only exist online. Competition between traditional retailers and e-tailers can be fierce. In 2002 lawmakers and tax officials from 40 states agreed to enter a voluntary pact to collect online sales tax after “brick-and-mortar” stores complained that online retailers that didn’t collect sales tax outside their home state had an advantage.

Until about the year 2000 most Web sites (other than blogs and user groups) were static and hierarchical in nature and did not allow visitors to contribute content. This era is often referred to as Web 1.0. In 2001 the Internet dot-com bubble burst as investment funding declined and the public grew wary of dot-com stocks. Many dot-coms closed or merged with other companies. As a result, Internet companies began to think about ways to improve the World Wide Web and better interact with users. Companies asked Web users for feedback on products and encouraged customers to create personal profiles and connect with others and share their interests. Technological developments such as widespread broadband, Flash application platforms, and improved browsers also changed the Internet. The confluence of these events marked the shift to Web 2.0, which, according to Terry Flew, author of New Media, involved a “move from personal Web sites to blogs and blog site aggregation, from publishing to participation, from Web content as the outcome of large up-front investment to an ongoing and interactive process, and from content management systems to links based on tagging.”

The transition to Web 2.0 fueled the emergence of social media, although some forms of social media had been around since the early Internet. Virtual game worlds, for example, trace their roots to the earliest multiuser games such as Mazewar (1974) and MUD1 (1978) that were played on ARPANET. Massive multiplayer online role-playing games became popular in the mid-1990s. The first online virtual world was Habitat, which was developed in 1986 by LucasFilmGames. Users were able to create digital representations of themselves called avatars and were able to interact with others in real time. Habitat lasted only until 1988. In 2003, Second Life launched. It offered a vivid, 3D experience that attracted millions of users. Second Life’s popularity peaked in the mid-to-late 2000s, although it still ranks among the most popular virtual social worlds.

Blogging began sometime around 1994. Jorn Barger, an industry pioneer with his weblog Robot Wisdom, was the first person to use the term blog in 1997. At the time, all digital conversation took place among communities using systems and online services such as Usenet, GEnix, and Bulletin Board. Conversations were held with user comments and messages threaded together on a virtual corkboard. Other users were able to read messages separated by topic or content and add newer threads to the conversation. Blogs became extremely popular in the late 1990s as blogging tools such as browser-based software and Web hosting services became accessible to ordinary users. Users of Wordpress.com, one of the most popular hosting services, publish 41.7 million new posts and leave 60.5 million new comments each month. Microblogs such as Twitter have also become popular. Tumblr, a combination microblogging platform and social-networking Web site, was launched in 2007.

Podcasts are episodic audio collections of information and opinions about a variety of topics (politics, music, gardening, etc.). They are created by individuals, groups of people, and companies and organizations. The term podcasting became popular in the early 2000s, combining the word iPod with broadcasting. But podcasting is not solely linked with the iPod, a popular MP3 device. Podcasts have become an extremely popular form of entertainment and information. In 2019, 51 percent of Americans age 12 and older had listened to a podcast, according to the Pew Research Center. This was an increase of 40 percent since 2011.

Other types of social media appeared in the late 1990s, but only took off in the next decade. Six Degrees, the first social networking site, launched in 1997 but only lasted until 2001, although it later returned on a limited basis. MySpace launched in 2003 and became the most popular social networking site on the Internet until that honor was passed to Facebook. In 2004 Facebook was started as a private social network to help students at Harvard stay in touch and network. Facebook became so popular that, in 2006, it became available to more users outside of Harvard. The company went public in 2012. Today Facebook is the most-popular social networking site; more than 2.4 billion monthly active users as of April 2020. Specialized collaborative social media projects such as Wikipedia, launched in 2001, only went mainstream in the last 15 years when people sought to create free repositories of information that could be continuously updated.

Great technological innovations in the last decade made it easier for Internet users to post photos and video and created strong interest in sites that let users share and comment on photographs and videos posted by others. Content communities such as Flickr (launched in 2004), YouTube (2005), Instagram (2010), and TikTok (2017) became immensely popular destinations.

Today social media sites are extremely popular, and they are expected to remain so for years to come. Artificial intelligence (including machine learning), natural language search, augmented reality, virtual reality, and other technologies (which are often cited as features of Web 3.0) are changing the way people use and interact on social media.

The Internet and social media have so quickly become an essential part of the fabric of daily life for so many people that it’s difficult to imagine a world without them.