Ajaxonomy Hacks Together del.icio.us Spy
It shows new sites as they are submitted to Delicious, along with a thumbnail of the homepage and a link. You are supposed to be able to filter the results by keyword and get notifications as well, although it wasn’t immediately apparent to me whether that functionality was working. It’s a nice hack that lets you watch the world bookmark the Web as it is happening. But Ajaxonomy needs to work on the filtering more to make it truly useful.
(Read more on the Ajaxonomy blog).