Well, it's an interesting idea. I've bookmarked Discord sometime last year, though mostly as an alternative for a lobby chat or in-game (but out-of-character) conversations.
For the record, I don't have first hand experience with it (yet) as I couldn't put it on my current schedules. Most of my info is from their rep materials, and my experience with things like Skype, TeamSpeak, and some prehistoric other things like IIRC, ICQ or MSN Messenger.
For the "in-development" phase, I thought I would stick to the forum system (like this one) as it provides an organized way for information/thoughts sharing and it is more forgiving on us (or anyone) with a heavily loaded schedule - we can easily track and answer new posts in our own pace, we don't have to be around all the time (though we usually are). Also, a "simple" forum we can surely integrate with our in-development Player Module once it's ready.
I'm kind of aware though that a forum requires a bit more "engagement" from anyone to post on and that it's a bit oldschool... well, slower paced..., so I planned to eventually revisit Discord as an interesting opportunity.
If you already have first-hand experiences with it, would you share your thoughts on the benefits Discord could offer us? Thanks! :)