Mastodon is a non-commercial alternative to X (formerly Twitter) and Instagram.

For what?
Mastodon can be used to share information, showcase projects, and interact with other users. Posts (called toots) appear in chronological order and are not filtered by algorithms. The platform is decentralized: there is no central authority or company that controls the data or sets universal rules. Instead, individual communities with thematic or regional focuses establish their own guidelines for data, communication, and content.

For whom?
Anyone can create a free Mastodon account. Registration requires an email address, a username, and a password. The username is publicly visible. Providing the real name is not necessary.

How?
Mastodon can be accessed via the following page:  https://joinmastodon.org/de
A documentation on how to use the tool can be found here:  Link

Setting up an account
Users can registrate for a server within the Mastodon network. The servers are called instances. Many instances are publicly accessible, while some require an invitation or a specific focus in their content. When choosing an instance, it is important to check the content focus, moderation rules, and data protection policies.

Important

• Mastodon does not store any personal data for advertising purposes. Data processing is carried out by the respective instance. Therefore, you should check where the instance is hosted and which data protection guidelines apply. 
• Personal data and images should only be published with the permission of the people visible within them and/or the creators.