From mine own experience with online text-RPGs, I'd actually recommend running it in our forums. Create a separate RPG subforum: This would allow us to post rules, setting info, character descriptions etc. in separate thread; it would allow us to collect all RPG threads in the same place and not let it spill over into the rest of the site/forums, while also providing an avenue for people to come at watch our story progressing.
Most importantly, however, it would create a stable text environment without particular time constraints. This is good for two reasons: 1) We live in vastly different time zone, so a forum-based RPG relieves the need to have everybody present at the same time; 2) It'll allow people to partake at their own pace, reread what's already been said, and compose their posts without the stress of getting left behind looming over them like it easily does in instant messaging environments. The latter is important because it'll help prevent a lot of stress-based anxiety, which (speaking from experience both as a player and GM) can be quite crippling, especially for first-time roleplayers or people with poorer English skills who will likely have enough performance anxiety to deal with as it is. Keeping it on something realtime like Discord or IRC would just stress me out by constantly making me worry whether or not I'm missing out on something.
The online RPGs I've partaken in have been held either on forums (such as LancersReactor or StarCraft Legacy) or on Facebook. Both work just as fine for the purpose (though fb naturally precludes anonymity, which may be a problem for some). The GM we had on fb rolled our dice for us whereas we players just wrote our actions and dialogue. It worked pretty well, as we trusted our GM, though it should also be said that we all knew each other more or less personally.
In any case, I'm very interested. It's been too long since I got to roleplay, and I've never done a Foundationverse one. This should be interesting. :)
