Yes. People are commenting on that here.

That sounds reasonable. What about if I use rich text in my posts? Will Mastodon try to show something or it won’t even recognize the post at all?

That’s not a compatibility table, that’s a comparison table (literally from the table itself). I’m not looking for what Firefish can do and Mastodon can not, I’m looking for how are those features interpreted in Mastodon. I’m concerned about discoverability and access. Right now Mastodon has way more users than Firefish and I wouldn’t like to post things only to end up being visible only by people with Firefish accounts.