Tumblr is a microblogging and social networking platform where users can post multimedia content and follow other users' blogs. Launched in 2007, it allows for the easy sharing of text, photos, quotes, links, audio, and video content. Users can customize their blogs with various themes and interact through reblogging, liking, and commenting on posts. Tumblr is known for its diverse and creative community, encompassing various subcultures and interests.