Unfortunately, the 12 minute tutorial video on del.icio.us seems unavailable to view, but the article Several Habits of Wildly Successful Del.icio.us Users is terrific! http://slackermanager.com/2005/12/the_several_hab.html
I did set up an account and posted a few bookmarks. Looking at the del.icio.us pages of some of the libraries listed on MD Libraries Learning 2.0 can lead off in a lot of different, interesting directions. One site that I like particularly is on the San Mateo page, Lib Site http://libsite.org/ .
One of the hardest things about del.icio.us is typing the word, getting those dots in the right places!