* The shut-down seems to be driven by some rather extensive technical problems, traced back to hacker attempts and security vulnerabilities, that would take entirely too long to address. (I wouldn't have tried to fix a volunteer site I run with this level of problems.)
* To be clear: while there are security issues, the site is currently secure, and info you've entered on the site isn't at risk.
* The site manager, Anglachel, said she's working with some sites to try to see if certain parts of the site can be archived. Specifically, she's working with Orchard CMS to see if their Resources section can be saved.
HASA was my first home in not only the Tolkien fandom but fandom generally. My connection these days is mainly nostalgic, but that's a real thing. It gave me my first toehold in adminning and helped me develop the confdence I needed to take on Challenges. Most of my friends were HASA members (and quite often HASA admins) at one time or another, and I have nothing but respect for what Ang, Gwynnyd, Cel, Dwim, and all the other volunteers did there. That's just a list off the top of my head, btw - not meant to be exclusive or even all that thorough! More objectively speaking, HASA is also a really nice collection of fanfic and research on Tolkien canon, and I'll be very sad to see it go, though I do want to emphasize: looking at the work it would take to address the technical issues, I completely stand by this decision and would have done the same. Not that my approval matters all that much. As I said, it's been a while since I've been heavily involved.
I hope people who were hosted exclusively on HASA will upload their fic elsewhere. I've had good experiences with Many Paths to Tread and the Silmarillion Writers Guild in terms of finding community, and while I had to leave Stories of Arda years ago due to ideological differences with that site's admin, SOA is another great collection of Tolkien fanfic with some simply lovely reviewers. (SOA's site admin is an excellent woman, btw; I couldn't keep posting there in good conscience myself, but that doesn't mean I wouldn't recommend it to others.) And of course AO3 is open to all fandoms. I've got all my stories posted there and have invite codes if anyone needs them.
Again, that's just the first sites that jump to mind, ones I've used myself and had positive experiences with. Not exclusive or even all that thorough.
But all of that's a bit secondary. We'll get more details as they're available, I'm sure, and things will work them out. For now, I'd just like to say it once more, to everyone who wrote, reviewed, donated or especially volunteered with HASA over the years: Thank you.