So I've been seeing people be able to type extravagantly long paragraphs on Mastodon. I'm wondering. Is that some kind of perk or something? How do I unlock this ability to type past 500 characters? I've got a lot of things to say!
@feditips - care to chime in on this question?
I think it's configurable per server/node.
Your local system has to store all the messages, so it gets to make the decision about how big they can be.
Short answer: some servers have the character limit altered by the admin so people can type longer messages.
Long answer:
Standard Mastodon has a 500 character limit built into the software that runs the server. Server admins cannot alter this.
However, Mastodon is part of the Fediverse which runs on open standards that anyone can use, including different Fediverse software.
Some servers run modified versions of Mastodon such as "Glitch" or "Hometown". These are pretty much the same as Masto but they have altered or additional features, including the ability to change character limits.
Some servers run completely different software (for example Friendica) where there are much larger character limits built in.
You won't notice people are on different software when you're using the Fediverse, because messages federate onto whatever software you're using. For example, I'm on a server running Glitch Mastodon, which is why this reply is so long 
@feditips @pseudonym Thanks kindly for the words of wisdom. Just trying to get my legs in this new environment after being on centralized social media for so long.