Discord
Downfall has moved mainly to Discord for both in-game voice chat and out-of-game collaboration. Discord is free and runs in both a browser and an app.
Join the <Downfall> Discord here
Though <Downfall> was raiding before Facebook even existed, these days the <Downfall> Facebook page is quite active.
Archive
The old <Downfall> guild forums site is frozen in a non-interactive state. New posts, comments, and user account creation are all disabled. The site is also locked behind an .htaccess login and password.
Simply ask Garreth for the credentials to access the old <Downfall> guild website.