Due to a recent (at time of writing) major PHP vulnerability, I've decided to stop running this ArkhamDB instance. Sorry for the lack of notice for the two people who were still using it :). My gaming group has switched to arkham.build, which is mostly just better anyway. Certainly easier to maintain custom content for, at least.
You can download an archive of all of the (public) decks as JSONs. These can be imported into arkham.build easily if they didn't use any custom content, but will need some manual fixing of ids if they were. This GitHub repo contains all of the card data (including custom content), and this one contains the modified server code to support some of it, if you wanted to run your own instance. Have fun!