I am building a news magazine blog for a large spiritual community. We want there to be one main blog which is kind of a portal for news for the whole global community. There will be about 100 blogs for city centers with their own news. I want the main blog to pull posts from the other blogs all into the central one. This is similar to the 'recent post' functionality seen in a few plugins (ie. http://wpmudevorg.wordpress.com/project/AHP-Sitewide-Recent-Posts-for-WPMU or http://www.callum-macdonald.com/code/sh-global-posts/)
I also want to moderate the posts that show up on the main blog. And I also want to view on the main blog all global posts for each category. I know this can be don with tags ( via http://ocaoimh.ie/2008/10/01/wordpress-mu-sitewide-tags-pages-031/) but can it be done with categories.
One last thing, is that I'd like to show the blog content of the sub blogs within the main blog as if it were still in the main blog theme, not going out to the sub blog.
any advice on which direction to go in and which to avoid would be very helpful. thanks.