So a group of some friends of mine wanted to try an experimental structure  
they called Storycaravan. In Storycaravan, blog posts made by members of 
the group would be echoed onto a central, forum-like site which would give 
each post its own, separate comment thread. Commenters would have to formally 
register with the site, and when someone made a new comment, the post on 
which the comment was made would pop to the top of the page, like on most 
forums.

It dawned on me that WordPress could make just about all of those things 
happen already. The only piece I would have to supply was the sort: the means 
to bring a post to the top of the page when it got a comment. (WordPress 
already has a Recent Comments widget, but it turned out not to be very 
reusable for this purpose, for a lot of wacky reasons.) So here it is: 
Blogcaravan, my first WP plugin.

There’s a huge amount it doesn’t do, and it may be doing even less in the 
near future – I may be able to do a better job of filtering the functionality 
to leave pages alone when appropriate. But I love the notion that by keeping 
functionality narrow, I can support a lot of unexpected new combinations. 
(For Storycaravan we’re blending it with the FeedWordPress aggregation 
plugin.) I hope it will be of use to people who want to do forum/blog hybrids 
without starting from forum software.

It probably only works with MySQL at the moment (take a gander at that cast()
statement).