If you are a del.icio.us user, you may be interested in knowing that del.icio.us is testing some new features. If you didn't receive an invite (I didn't, which doesn't mean much...) then you can request to be added to list.
I do hope that this will also mean more functionality in searching. For example in the Cataloging links page which is populated by del.icio.us links, it would be great if I could include a search box limited to user ... Currently, searching by user is limited to being logged in.