Oh yes probably the most important bit is that I don't like the idea of stable URLs anymore. Imagine a search result that shows:
Foo calendar item in bar club.
your_url/object/1234
MP3 folder in music club
your_url/object/5678
So there needs to be an inexpensive way of calculating an object's url with a proper result. Dave has some thoughts on this, maybe he can post them here.