Just look around: there're piles of instant messaging and VOIP applications. What to choose? Developers don't know what to start with to keep spoilt users sitting on the edge of the chair.
Affinity Networks selected alcoholics and addicts to be their target audience and developed nice software Anonymous Sober Chat for AA where people can share stories and discuss problems. Anonymously, of course.
It's only for iOS and you can try this app if you're interested in group messaging, as well.