This article by Martin Belam reporting on a talk by Nigel Smith on the closure of BBC Archer's messageboard prompted me to gather links about this topic.
I asked on Quora a while back, prompted (probably) by one of Martin's earlier blog posts on the subject, How can people using an internet forum prepare in case the provider shuts it down?. No answers were forthcoming.
Earlier this year I said
When Jeff Attwood does something new it's worth paying attention: http://t.co/SzW4QbXRSo that new thing is Discourse, making quality forum software available. But the question still remains "if someone else is hosting [a forum] and they want to shut it down, can the community be sure that they can get at the content?"
— Paul Morriss (@paulmorriss) February 6, 2013
When we moved house I spent a while on the uk.rec.motorcycles and the uk.rec.gardening Usenet forums. Quite a different style between the two. I need to see if the two people who were feuding on ukrg are still doing so.