@Jeffro, thanks for promoting Ron's work, he and Andrea are true WPMU rockstars:)
@Ron, thanks for releasing this plugin, congrats and good luck!

@Dgold - Here's a use case that I have in mind. Let's assume I have an MU setup running a clothing store and I have 85 categories in the main blog, one for shoes, shirts, pants, etc. After running this for awhile, let's say I want to start creating niche blogs that focus on one kind of apparel. I could simply create another blog called shirts in my MU setup, then use this plugin to export only posts in the shirt category and populate this new blog.