An online streamer is like someone who plays games or sings or talks in front of a camera and shows it to other people on the Internet. You know how sometimes you watch videos on YouTube or TV? Well, that's kind of what an online streamer does, but instead of making a video and uploading it, they play the game, sing or talk live on the Internet.
People watch online streamers because they are usually very good at playing games or entertaining, and it is like watching a friend play games or do something fun.
An online streamer connects their camera and computer to a website or app called a streaming platform, and when they start broadcasting, people from all over the world can watch and chat with them.
Just like watching a TV show or a movie, online streaming can be a lot of fun!