What are some alternate ways to continue contributing answers, given the website is going dormant soon?
One way - start a blog. Feel free to edit the answer to post your blog's address.
One way would be to start a blog where you post questions (ones from the site maybe, or ones that you create, or whatever), and then answer them.
I'm starting one and while it won't have all the cool tools and formatting things, I will be able to get my fix of answering math questions.
The address is here: https://mathfact-orials.blogspot.com
I'll be focusing on combinametrics and I'll also be doing a lot of business/accounting/financial/investing questions.
Start a website/blog.