Cool a tagcloud for del.icio.us, and a search for tags facility…you can even combine tags in your search.
Although you still have to use the address bar to search for a user, unlike del.icio.us tag search (3rd Party).
I also noticed when you browse items within a tag, if you scroll to the end there is a link to view recent popular items within this tag
(this is handy as there is only a bunch of tags to choose from on the popular page, so now this can be done with any tag).
I’m not sure if my recent discoveries are new or old, but they are exciting none the less.