I have had a discussion with an admin there (which you can read here) and basically, if there's enough interest, they will look into supporting the XOOPS/CBB community.
This is a service I would really like to try out, and from their own stats, they reckon they have exchanged 45,480 posts over 677 forums, so it looks like it's worth a try.
So, I ask that anyone who's interested in improving traffic to their site to visit PostFusion for more details and post in the feature request forum to show there's interest in their service from the XOOPS community.