Reddit is an American proprietary social news aggregation and forum social media platform. Registered users submit content to the site such as links, text posts, images, and videos, which are then voted up or down by other members. Posts are organized by subject into user-created boards called "subreddits". Submissions with more upvotes appear towards the top of their subreddit and, if they receive enough upvotes, ultimately on the site's front page. Reddit administrators moderate the communities. Moderation is also conducted by subreddit-specific moderators, who are unpaid volunteers. It is operated by Reddit, Inc., based in San Francisco.