I have started using del.icos.us only today and have become an instant fan. They have a cool plug-in to easily bookmark pages and see their ranks getting better. Moreover, I have subscribed to its popular bookmarks which give a list of good sites.
While using it, I found http://workfriendly.net/ -- a site for hiding the site and bypassing firewall for use at workplace. There are many more similar sites for doing such things. Tab-renamiser is another firefox plug-in for hiding tabs. Fortunately, I don't need any of them. My work-place is sort of cool in this respect. Moreover, my employers are not that techno-savvy (:P) to understand even what digg or google reader is. I hope this state will continue for years to come.