Mastodon is a free and open source alternative to Twitter/X. You can sign up for an account here.
It’s part of the fediverse, meaning that it participates in some other social networks as if they were in the same network.
- Threads (by Meta) — Is in the process of rolling out federation. Status here.
- Bluesky — Bluesky is another distributed social network, but doesn’t natively partipate in the fediverse. However, a bridge exists here so that full federation effectively happens.
- RSS feeds — Not a social network, but a lot of blogs and podcasts offer RSS feeds. If you have an RSS feed, you can be notified when they post. However, with birb, you can also subscribe to a blog or a podcast as if it were any other social media account. It’s not full federation, but it is a way to add content into your Mastodon feed and view it in fossil.
When one of the above networks federates with the fediverse, that means you can follow accounts or like and boost posts. It should work in both directions, so acounts in bluesky can also follow and interact with your posts.