In Threaded RSS readers for Yahoo! and Google Groups EirePreneur nails how we can use OPML to make feeds work with discussion forums:
Yahoo! will provide you with a single OPML URL for all your Groups subscriptions - each node at the top level will correspond to a Group. The next level down will be a node corresponding to each topic lead and the leaves will be feed items (individual topic posts), or sub-nodes as necessary.
While EirePreneur goes on to say that this is where feed grazers are strong I don’t see how a traditional 3-pane feed aggregator with a live OPML subscription feature won’t work either.
