There have been a few requests on some of the Orkut metadiscussions for categories to organize communities into. Hopefully, that'll be the next thing they add -- the thing they just added is a way to categorize friends more.
Now you can indicate to what degree you are acquainted with someone, as opposed to merely indicating that you are acquainted with them. Significant improvement, yes. Helpful, yes. I'm sure Marc Canter's getting more out of it than me, but I still found it useful.
I still have 119 communities to sponge through, though, so I'm happy about the change, but I still can't do what I'd like to do -- keep up with different groups of communities properly.