Credit:
Since April of this year, the social bookmarking del.icio.us has provided the option to add users to your network and gain fans - people who like your bookmarks and have added you to their network. Last night they extended this functionality even further - you can now create a "network badge" to put on your site. The badge displays the message "Add Me to your del.icio.us network" as well as some optional stuff like your del.icio.us username, your network count and your fan count. Here's Mashable's button (although I don't use del.icio.us much these days).