The SocialList plugin does the following:
SocialList is a WordPress plugin that adds a page to your admin area allowing you to view details on submissions of your pages to social bookmarking sites. Currently only del.icio.us and digg are supported, but I’m hoping to add more in a future version.
The creator says that he only tested the plugin on his installation, and many of the commenters seem to have encountered problems, so I’m not sure if it’s a good idea to install it until things have been ironed out. But it’s an interesting idea, and yet another way to try to satisfy the analytics obsessions of bloggers!