I'd really like to play Nomic, preferably online, and I'm interested in joining Agora. How do you keep track of who is a current player and get the game back in motion?
Agora's not stopped, just slowed. :) Most parts of the gamestate are kept track of by elected officers posting periodic reports to the agora-official mailing list (the amount of automation, if any, used to create these reports varies). Sometimes officers also maintain a web version - notably, this is usually the case for the rules, which are currently maintained at:
(agora-official is for reports, agora-business is for taking game actions, and agora-discussion is for discussion.)
For the list of officers, search for [IADoP]; for the list of players, search for [Registrar]. I post as "omd".
Just for fun, another link that I should mention, since the one on agoranomic.org is out of date (again, I need to fix this): almost 3000 old judgements on rule interpretation, most of which are long obsolete due to the relevant rules being amended or repealed, but some of which serve as (non-binding) precedent -