I mean email, chat, etc. -- I know about
nxtty but am having trouble finding out whether there's anything else out there or if someone's working on a Blockchain-based communications app.
What do you mean by a blockchain based communications app? You mean by encoding the messsages into the blockchain, because that is really the only way the blockchain could be utilized for that. If so, then probably not, and I hope to god that such an app is never created. We don't need spam like that to bloat the blockchain with useless crap and people running full nodes won't want to store it.