Either this is hypnotic, or I have way too much free time. Del.icio.us Spy, at http://www.ajaxonomy.com/deliciousspy/ , shows you bookmarks as they’re being added to del.icio.us, along with a screen shot and occasionally a little context.
If you don’t want to see every last bookmark being added, you can also filter by tag. If you happen to choose a tag that doesn’t get updated very often, you can have the site play a sound for you every time it updates. And finally, there’s a pause button if you see some links that you want to investigate before they scroll off the screen. (You can also save links for a single session if you like.)
Del.icio.us Spy is also open source, so you can install it on your own server if you like. You can get details and a link to the source code at http://www.ajaxonomy.com/2008/web-20/ajaxonomys-delicious-spy-released .