What is social media?

Social media is the set of internet platforms where users create profiles, publish content, and engage with the content other users publish. The platform is the venue, the audience is the publisher, and the line that separates social media from the older media (television, radio, newspapers) is whether the people watching can also post back.

What is social media?

Social media is the category of internet platform built around the user-as-publisher model. The platform supplies the venue (the feed, the inbox, the profile pages, the recommendation system, the moderation rules), and the audience supplies the content (the posts, the videos, the photos, the comments, the replies). Everything that follows from social media as a working medium follows from that underlying inversion: the audience makes the content the platform sells advertising against.

Britannica's working definition, in its social media entry, is “a form of mass media communications on the Internet through which users share information, ideas, personal messages, and other content”. Wikipedia's version in its social media entry is “new media technologies that facilitate the creation, sharing and aggregation of content amongst virtual communities and networks”. Both definitions put the same thing at the centre: the user-generated content and the network that surfaces it.

The category is now the dominant medium on the open internet. DataReportal's April 2026 global social media report shows 5.79 billion user identities, roughly two-thirds of the world's population, spending an average of 18 hours and 36 minutes a week on the platforms across all of them combined. Year-on-year, 294 million new identities joined in the last 12 months, an annualised 5.4 per cent rate, or about 9.3 new users every second. Social media has moved from a category to infrastructure, and the share of the world's media consumption that runs through it has grown for every year since the late 2000s.

What makes a platform social media

Not every internet service is social media, and the line between social media and the rest of the internet is sharper than the casual usage of the phrase suggests. Four working traits are present on almost every platform people call social media and absent on most platforms they do not.

The six types of social media

Most working classifications of social media land on six broad categories, with most modern platforms sitting across two or three of them rather than inside one cleanly. The working version is below.

The platform landscape in 2026

The global usage rankings have been remarkably stable since 2022. DataReportal's April 2026 numbers (above) put the top five by advertising reach as YouTube, Facebook, TikTok, Instagram, and LinkedIn, with WhatsApp and Messenger sitting alongside them on the messaging side. The working state of each platform is below.

The history, from SixDegrees to TikTok

Social media as a recognisable category is younger than most of the people using it. The timeline below covers the platforms that mattered to the development of the modern shape of the medium.

1. 1997, SixDegrees.com. The first recognisably social-media platform. User profiles, friend lists, the ability to message inside the network. Shut down in 2001 but established the template everything that followed borrowed from.
2. 2002 to 2003, Friendster and MySpace. The first social networks to reach mass-market scale. Friendster peaked at over 100 million users; MySpace became the largest social network in the world in 2006 before being overtaken by Facebook. MySpace also established the customisable-profile and music-led shape that influenced platforms for years afterward.
3. 2004, Facebook. Launched at Harvard, opened to other universities, opened to the wider public in 2006, and grew into the largest social network in the world by 2008. The algorithmic news feed (launched in 2006, controversially) set the template every later platform copied. Bought Instagram in 2012 and WhatsApp in 2014, consolidating most of the modern social-media advertising market under one company.
4. 2005 to 2006, YouTube and Twitter. YouTube launched in 2005 and was bought by Google in 2006; Twitter launched in 2006 and made microblogging the shape of public conversation for the next decade. Both platforms remain part of the global top tier in 2026.
5. 2009 to 2011, the mobile-first wave. WhatsApp (2009), Instagram (2010), and Snapchat (2011) all launched within the same two-year window and all three were mobile-first from the start. The shift from desktop-and-web social media to phone-and-app social media dates to this period, and the platforms that did not make the transition (most of the older networks) did not survive it.
6. 2012 to 2016, the consolidation. Facebook bought Instagram (2012) and WhatsApp (2014); X bought Vine (2012); LinkedIn was bought by Microsoft (2016). Most of the platforms that had been independent in 2010 had been acquired or had failed by 2016, and the global landscape consolidated to the small handful of companies that still run most of it in 2026.
7. 2016 to 2018, TikTok. ByteDance launched Douyin in China in 2016 and TikTok internationally in 2017, then merged TikTok with Musical.ly in 2018. The For You algorithm produced the first non-follower-led mass social platform, and the shape of TikTok's algorithm forced every other platform to rebuild around short-form vertical video through the 2020s.
8. 2020 to 2026, the short-form era and the rest. Reels launched in 2019 to 2020, Shorts in 2021, and the platforms have spent the years since pushing their short-form products to the centre of the user experience. The independent challengers (Mastodon, Bluesky, Threads, Discord, Substack) have grown to meaningful size without displacing the major platforms, and the global category has reached the 5.79 billion user mark DataReportal reports for April 2026.

How social media is actually used

Social media has stopped being a single use case and is now a stack of overlapping ones. Most users move between several of the patterns below across a single day, and most platforms now design for several at once.

The major shifts since 2020

The shape of social media has changed more in the six years since 2020 than in any equivalent stretch since the late 2000s. The five biggest shifts are below.

1. Short-form video became the dominant format. TikTok's growth forced Reels (2019), Shorts (2021), and the other major platforms to rebuild around vertical short-form video. The grid feed, the static photo, and the long text post have all lost share to the 15-to-60 second video.
2. The algorithm replaced the friend list. Through the 2010s the feed was mostly chronological and ordered by who the user followed; through the 2020s the feed has become mostly algorithmic and ordered by what the platform predicts the user will engage with. The For You model is now the default rather than the exception, and the share of the feed coming from accounts the user actually follows has dropped sharply across every major platform.
3. The creator economy turned professional. Full-time-income creator businesses, agency representation, the rise of subscription platforms (Patreon, Substack, OnlyFans), the LinkedIn creator economy on the B2B side. The shift from social-media-as-hobby to social-media-as-career is the single biggest economic change inside the category since 2020.
4. AI moved from the back end to the front. Algorithmic recommendation was always machine learning; since 2023, generative AI has moved into the visible surface as well. AI-generated captions, AI-generated images, AI-edited video, AI-summarised feeds, AI chatbots inside the messaging products. The line between content created by a person and content generated by a model has blurred enough that most platforms have started labelling AI-generated content explicitly.
5. Regulatory pressure caught up. The EU's Digital Services Act (2024), the UK's Online Safety Act (2023), the US TikTok divestment process, Australia's under-16 social media ban (2024 to 2025), age verification rules in multiple jurisdictions. The unregulated growth period of the 2010s has ended, and the major platforms now operate under a substantially more complicated rules-and-compliance regime than they did five years ago.

Common misconceptions about social media

1. That social media is a single thing. The category covers six major types of platform, dozens of working products, and use cases ranging from one-on-one messaging to broadcast video to community forums. Talking about social media as if it were one unified medium is the same mistake as talking about television and a phone call as if they were the same thing.
2. That young people have stopped using it. The pattern most reports describe is younger audiences shifting between platforms, not leaving the category. The time-spent number for under-25 audiences in 2026 is higher than the overall average, not lower; the platforms that share is concentrated on (TikTok, Snapchat, YouTube, Discord) are different from the platforms older audiences use, and that platform shift gets reported as a category exit when it is not one.
3. That organic reach is dead. Organic reach on Facebook page posts has fallen below 2 per cent and on Instagram feed posts is in the 2 to 4 per cent range; it has not collapsed across the whole category. TikTok, Reels, YouTube Shorts, and LinkedIn continue to push organic content to non-followers in ways that produce reach numbers a 2015 marketer would have found astonishing. Organic reach on the legacy surfaces is hard; organic reach on the working ones is not.
4. That every brand has to be on every platform. The brands that perform best on social are usually deliberately present on two or three platforms rather than thinly spread across six. The right choice depends on where the audience is and what the brand has to say; being on a platform the brand cannot service properly is worse than not being on it at all.
5. That algorithms can be tricked. Most platform-hacking advice (the right hashtag count, the right post time, the secret engagement trick) has a half-life of about three months before the algorithm changes again. The brands and creators that grow consistently on social media in 2026 are doing so on the back of the content itself, not the tricks layered on top.
6. That follower count is the same as audience. A 100,000-follower Instagram account is not an audience of 100,000; it is a follower base from which the algorithm shows each post to between 2 and 40 per cent on average, and from which engagement comes from a much smaller core of active followers. Reach, engagement rate, and community size are the meaningful measures of audience; follower count is the marketing number.

For the surrounding context this entry sits inside, the organic marketing entry covers the unpaid side of social media work, the algorithm entry covers the system every modern social platform runs its feed on, the community entry covers the dense-engagement layer that sits underneath the wider social presence, and the brand awareness entry covers the most common outcome social media is used to produce on the marketing side.

The matching tools on this site cover the planning and measurement side of social media work. The social media strategy template is the framework most teams use to map content pillars and post types across the platforms that matter, the engagement rate calculator benchmarks the audience response against the working platform medians, and the social media audit template is the quarterly framework for the wider review of a brand's presence across the platforms it is on.