After trying a variety of different tools, I’ve come to some conclusions:

• IRC chatrooms work much better for discussion than web forums, even though they are synchronous and so are less convenient.  Unless people know each other well and really care about talking to each other, exchanges on web forums always feels obligatory.
• Including a picture of yourself makes a huge difference in how well peers remember each other and how interested they are in engaging–an interesting avatar can be ok too, but I think human faces, especially if they can be seen clearly (are big enough, in focus, etc) really makes people feel more connected.
• The simpler the better, even if it means a little less functionality, especially for people unfamiliar with tech.
• The less experience people have with tech, the higher expectations they have for it’s performance.

I’m sure there will be more, but this really stood out to me.