I've Seen Many Sites Using This Wordpress Plugin But I Dont Know What It Is Can Anyone Tell Me What Wordpress Plugin Is This?
http://wordpress.org/extend/plugins/simple-social-bookmarks/ or http://wordpress.org/extend/plugins/social-bookmarks/ or http://wordpress.org/extend/plugins/sexybookmarks/
It is Digg Digg and available at http://wordpress.org/extend/plugins/digg-digg/ Be forewarned. This plugin does make external calls to get the number data to display in the icons from each of those sites. While this may look really neat, it is a resource hog and adds to your page load time. I am not sure if this data is cached or not, but if the option is there then opt in to it. Personally, I think buzenko's 3rd suggestion of SexyBookmarks is a more conservative and elegant choice.
A WordPress Plugin is a program, or a set of one or more functions, written in the PHP scripting language, that adds a specific set of features or services to the WordPress weblog, which can be seamlessly integrated with the weblog using access points and methods provided by the WordPress. With WordPress Plugins, you can modify, customize and enhance your WordPress blog easily.