octothorpean.org will shut down around June 30, 2020. It had a good run.
Teams are still playing—there's about one new team per day. In May, three teams solved the big scary metapuzzle.
So why shut it down? octothorpean.org is built "on top of" Google App Engine. Google App Engine's API is changing; and Octothorpean would need some adjustments in the near term. In the medium term, App Engine won't have a way to send email. Octothorpean assumes there's a way to send email. With some further adjustment, it could stop assuming that… But that's adding up to a lot of effort; and I'm pretty distracted these days.
octothorpean.org had a good run. Six+ years! Time to let it go.