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A free, open-source, decentralized social network. Anyone can create or join an "instance" of Mastodon, where an instance is a unique domain name, and instances can be "federated" with each other so someone using one instance can interact with users on another instance. Comparable to email, where a Gmail user can email with a Yahoo mail user and vice versa. Comparable to Twitter, but less corporate and fewer Nazis. However, admins can run their instances however they wish, and may choose to allow/prohibit/monitor content that includes racism and other -isms, pornography, violence, etc. The service allows posts to be placed behind a content warning (CW), and allows media to be marked as NSFW, and can be posted publicly, to followers only, as a direct message, or unlisted (where the post is public, but does not show in the federated timeline). Most instances allow posts to contain 500 characters available, and some instances allow much longer posts. Posts are called "toots," and reposts are called "boosts," but instances can be customized to fit a theme or other preferences. Usernames are formatted as @username@instance.domain, such as @gargron@mastodon.social, where user @gargon is on the instance mastodon.social.
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