Last time I talked about the benefits of tagging your own bookmarks. But that's not all del.icio.us offers!
First, the front page is just a list of the 30 or so most recent bookmarks that anyone has added. This is a great place to find lots of random stuff. There's also a page of what's popular (as well as populicio.us, which has a list of the most popular links that were not bookmarked before yesterday). I've found lots of good articles and useful websites that way.
You can also look at the tags for all bookmarks. So, if you're looking for cool google-related stuff, try del.icio.us/tag/cool+google, or even just del.icio.us/tag/google. This to me is less useful than tags for your own bookmarks, but it's fun to just pick a random word and see what sites come up. Like trogdor!
Also, all of the bookmarks show how many other people have that site as a bookmark. So, I can see that someone else has bookmarked my iTunes info. I'm famous!
You can also get RSS feeds for all of those sorts of pages, if that sort of thing is your bag.
Well, that's about the cool things I can think of, so here ends the series. Play around with it for a while - I think you'll like it!