There's great discussion going on here about creating weblog aggregated from individual bloggers' categorized posts.
This would be a fun way to create an Austin blog out of the various AustinBlogger posts that talk about local events and places.
And a conversation about Shelley Powers ThreadNeedle application, which will create threaded discussions out of trackback threads (if I understand it right).
Which we could use to create a single threaded discussion out of the distributed conversation about geoURL applications.
I'm still reading up on the conversation, please correct me if I've summarized wrong.