An administrative announcement.
Q: What's this "Federation thing?"
A: A bunch of communities, on different servers, sharing /some/ but not necessarily /all/ of their traffic. Or, in some cases, none. It depends.
The User Guide has a good section:
A Mastodon instance for maths people. The kind of people who make \(\pi z^2 \times a\) jokes.
\) for inline LaTeX, and
\] for display mode.