I've made blockland chat systems before, way back years ago. It's not all that complicated. DC4F/Nullable and I used a Java server I believe, though something more lightweight would probably be ideal. Node.js or Python probably.
Basically, my thinking with BLG is that when I finish the features I'm working on, I'll move on to another one that I feel the community needs, assuming nobody else is working on it. I'm not here for competition, but I'm not afraid to move forward. Add-on hosting is only the beginning. In the past, I've announced too many features at once, and that's led to the project failing, which is why I haven't made any large commitments outside of add-on hosting yet. If someone else comes along and starts to develop, that's fantastic, I'll work with them and try to integrate things where they make sense.