I am pretty sure the most of bitcoiners have interest in BC as well as other open-source decentralized projects, the most popular of them being Jabber. Basically, it is an IM service (like ICQ, AIM, MSN), that... is distributed (so you can set up your own server). It is quite popular: many people have Jabber accounts even if they don't know about it (GMail/GTalk users, LiveJournal users, Facebook users (IIRC, since I never had a FB account) QIP Infium users...). It also has transport services, that you can register your other service accounts on and talk with those services' users within your Jabber client...
There are easy-to-install mods that add Jabber to the IM list for SMF forums, so this shouldn't be too hard.