Hmm.
I certainly could host Mastodon for free, and save the $12/monthly for more events, but... naah. 
In the past we toyed around with CDS-specific social media, I remember having set up a few experiments, but they never got any traction. It's like the mysterious two CDS channels on Discord, one of which has, at best, five citizens, and gets a new one every other year, when someone remembers their password long enough to invite another citizen
I think we already have a perfect "social media" thing, and it happens to be called Second Life. Sure, the in-world chat/group chat is perhaps at the 1997 stage and was never improved since then, but, alas, it just happens to be the one we use much more regularly.
Mind you, I'm not anti-Mastodon myself. I see some appeal on de-centralised, federated, text-based, mass-communication environments. Mastodon just happens to be a brand name (and a company) which became popular by cooking up an application using the open standard Activity Streams 2.0 format, which is, indeed, used by the free and open communication protocol ActivityPub, both designed by the W3 Consortium, the same bona fide organisation that reviews the Web protocols (HTML and HTTP, for instance) and is part of their Social Web Protocols suite. Anything which works with the ActivityPub/Activity Streams protocols can connect to the same 'federation' where Mastodon users 'live'.
Anyway... I have always had a few misgivings about the "new" social web decentralised, federation model. I'm not talking about the technology itself, which is awesome but rather the reasons for such 'decentralised' models. Mastodon, for instance, hopes to make money (in some way or another), and if they manage to grab, say, 90% of the ActivityPub-for-Twitter-like-social-media market, then I'm pretty sure they'll make their own servers incompatible with the remaining 10% and thus 'corner the market'. For a while, you might still connect with your free server to Mastodon's 'federation'... but soon you'll have no other choice but to pay for the privilege of connecting to 'their' federation. And at some point there will be so few people paying to connect that Mastodon will justify just dropping them off and make 'their' federation the de facto successor to Twitter/Threads and as incompatible with any 'free protocol' as Twitter and Threads currently are.
This happened so many times in the past three decades that it's not hard to 'predict' that it will happen again. Someone posted a long article on this very subject, which sort of echoes my own thoughts.
Personally, I don't really "trust" companies such as Mastodon. They might even be well-intentioned today, in 2023. But in 2025?... they might get acquired by one of the industry giants for a bargain (they are not really very valuable — they just got lots of media attention, and that's always a good reason for corporations acquiring such companies ). And then two things may happen: everything gets shut down (the Meta/Facebook approach to 'competition') or absorbed into the companies' own technologies (like, well, pretty much everybody does... but perhaps Autodesk comes to mind) so that it becomes indistinguishable from their own product offerings, and, as such, will only work with those.
In conclusion: while I'm certainly going to do my own experiments with Activity Streams/ActivityPub, it most certainly won't be using Mastodon Besides, Mastodon is written in the Ruby programming language, one that I hate (long story), ranking high on my list of never-to-install-anything-written-in-these-programming-languages (the other one at the top of the list is Java). Personally, for my experiments, I'll stick to something much interesting such as GoToSocial (aye, it's compatible with the Mastodon flavour of ActivityPub...).
