@mpj17 that COULD be it. However, the ability to edit the maximum post length is fairly simple for Mastodon admins, just a few file edits.

@mpj17

other systems that implement #ActivityPub
Correct.

@mpj17 As you have already noted, the fediverse is more than Mastodon, other platforms can implement other length limits.

But also, different Mastodon instances (servers) set different length limits for posts.

@mpj17@mastodon.nz That's right, Mastodon is not the only service in the Fediverse and is basically just a kind of browser in the network.
I am writing to you here with the software Calckey, which can do much more than mastotodon.
And by more I mean more

Have a look at the link, it's just a little help. https://jointhefediverse.net/?lang=en-us

In reality there are about 150 different services active in the Fediverse. Including video services like #Peertube and #Pixelfed for just pictures, ala Instagram

If you want to know more, just get in touch. 👍

@mpj17@mastodon.nz

Yes!

Okay, this is a very short and simplified answer.

The federated universe or #Fediverse is a network of thousands of independent instances (nodes, servers, systems).

Each instance is free to select the software, they want to run, as long as they agree to speak a common language to communicate to each other: Currently this is very often the protocol #ActivityPub.

So different software may have different ideas in mind, they may focus on different topics, e.g. micro-blogging, macro-blogging, images, videos, etc.

That also means different capabilities, e.g. regarding the maximum length of a post or if it allows simply formatting or not etc.

Many server software is #OpenSource, so everyone can not only use it, but also modify it. So besides the different software types, you can also have variants of it.

And as #ActivityPub is an open standard, you can also develop your own approach or a full new solution.

Just some examples of #Fediverse server software, that you can use to run and operate an instance in the world-wide federated universe:

#Mastodon
https://en.wikipedia.org/wiki/Mastodon_(social_network)

#Friendica
https://en.wikipedia.org/wiki/Friendica

#Misskey
https://en.wikipedia.org/wiki/Misskey

#Pleroma
https://en.wikipedia.org/wiki/Pleroma_(software)

#Pixelfed
https://en.wikipedia.org/wiki/Pixelfed

#PeerTube
https://en.wikipedia.org/wiki/PeerTube

Enjoy the open world (universe!) and the real social media... and a nice weekend... :-)