I think that one of the best things that could happen in WPMU would be for us to develop a global categories app.
The plugin is there in mu-plugins but I'm not savvy enough to figure out how to make it work, basically I reckon that the software would benefit immeasurably by allowing the following.
1. User writes post
2. User goes to regular 'categories' and selects / creates which (if any) of their personal categories they want to post to
3. User selects from global categories menu (for, say edublogs this could be things like: primary science, distance education, archaeology, the internet etc.)
4. Posts allocated to global categories (I'm guessing this'd be off by default) are presented at the global categories page through either just titles or titles & excerpts which obviously link back to the original blog.
-Global categories pages need feeds (obviously)
-Need to be able to simply generate a list or search (quickserach as in K2?) function to sit on the front / community page
-Need some options such as 'titles', 'titles + excerpts' or 'full text'.
-Need some way that people can suggest new global categories, don't really want creation to be open slather as then you get the same problems as Tags... (i.e. 'EdMedia' and 'EdMedia 2005' are different tags) but do want the capacity to be able to have new ones suggested through the form.
How hard do ya reckon this might be to put together y'all?
Can you see some value in it?