An online streamer or live streamer is a type of social media influencer who broadcasts themselves online through a live stream to an audience.

Online streaming arose in the mid-to-late 2000s, originating on sites like YouTube where users could upload videos of themselves in the form of vlogs or Let's Plays. While not all content featured a live audience, users were still able to gain a sizable following and make a living from their content. Other sites like Twitch increased this popularity by offering innovations such as video clippings and pay-for-play. Due to the potential for high earnings from multiple income streams (e.g., ad revenue sharing, endorsements/partnerships, subscriptions), streaming has become a much-yearned-for career option.

Let's Plays have been the most popular streamers by far since the beginning of live streaming. Today, the majority of streamers make their living from doing Let's Plays, live speedruns, and walkthroughs of video games. The biggest video game streamers are PewDiePie and Ninja, who make millions of dollars each year just from streaming.

While the majority of professional and part-time streamers play video games, many often do IRL (in real life) streams where they broadcast their daily life. At first, many streaming sites prohibited non-gaming live streams as they thought it would harm the quality of the content on their sites but the demand for non-gaming content grew. Topics include answering questions in front of a computer, streaming from their phone while walking outside, or even doing tutorials. IRL streams are alternatives to viewers who do not necessarily like to play video games.

Virtual avatars, commonly known as VTubers, are a branch of streaming in which virtual avatars, occasionally paired with voice changers, are used instead of the streamer's face. There are multiple companies focused on the promotion, support and merchandising of VTuber talent, including Nijisanji and Hololive Production. In 2020, there were more than 10,000 active VTubers.

Pornographic streams are a way to directly communicate with porn stars. Camgirls and camboys broadcast while nude or performing sexual acts often on demand from viewers. Sites like Plexstorm have created a niche by streaming video gamers performing or showing sexual content including pornographic games.

A controversial form of live broadcasting where the host engages in shocking, dangerous, or humiliating activities, often to drive viewer donations. Popular primarily in Russia, Ukraine, and Poland, this format has also been observed in Finland and is associated with sensationalist content meant to provoke or entertain through extreme behavior.

Some streamers broadcast nearly all aspects of daily life for prolonged periods. For example, a Twitch streamer known only as "Emily" streamed continuously for over 1,100 days, sharing her routines, meals, and personal moments - highlighting the emotional toll and blurred boundaries of online performance culture.