It adds a list of XHTML graphic links at the end of your posts/pages that allow your visitors to easily submit them to bookmarking social sites.
The Social Bookmarks plugin for WordPress adds a list of XHTML compliant graphic links at the end of your posts and/or pages that allow your visitors to easily submit them to a number of social bookmarking sites.
Furthermore, the plugin adds a section in the WordPress Dashboard that lets you customize it. You can enable/disable social bookmarking sites and exclude specific pages from the plugin.
Also, you can add additional sites by uploading Site Packs to the plugin directory.