TL:DR – Mastodon is a decentralized social network. It consists of thousands of different sites, or instances, all running the Mastodon software but each with its own character, community, and rules. When choosing an instance to join, you are best served by choosing one that aligns with your interests and values.
You should consider the following when choosing your first Mastodon instance. Remember, you can always switch later and take any followers you gain with you.
Moderation: Mastodon instances are self-moderated with their own set of rules. Some are strict, others more permissive in terms of the content they allow. You need to find an instance with moderation policies that you are comfortable with.
Size: Size matters. Larger instances can be more active, which can be better but can be overwhelming. Smaller instances may have a tighter-knit community with more focused discussions, but you might find them less engaging.
Administration: It is worth knowing who owns and runs an instance. Often it is an individual but it can be a group or even an organisation.
Availability: Some instances are more prone to downtime or server issues. There is also the issue that for some instances, an admin may not have the finances to sustain it or even make a decision to close the instance at any time. It’s worth looking at the instance’s track record, how well it is supported, and also whether there is a notice period for closure.
If you have questions about a given instance, you can look at its public timeline and documentation, you can even post questions about it in the wider community. As a Sciencebase reader, you might like to consider the more popular instances that are used by the people I follow. You can find that list here.