Share and Follow
In order to maximize the potential of social media, you should incorporate buttons on your website that make it easy for people to share your Posts with their online contacts, friends, and followers.
The Share and Follow plugin inserts the familiar Share This Post group of buttons to the end of each post.
Share and Follow is one of many plugins that accomplishes this task, but it does it quite well. This plugin will display buttons for Facebook, Stumble, and Twitter automatically and also supports Digg, Reddit, Delicious, MySpace, LinkedIn, Hyves, RSS, Mixx, Print, Email, Google Buzz, Tumblr, Yahoo Buzz, Orkut, Sphinn, Vkontakte, Nujij, Picasa, Bookmark, Bandcamp, Moddb, IMDB, YouTube, Deviantart, Yelp, Feedback, Flickr, LastFM, Newsletter, Xfire, Vimeo, Foursquare, Dailymotion, Plaxo, SoundCloud, Coconex, Xing, Gowalla, Posterous, iTunes, Ya, Slideshare, Ning, Feedburner, Plurk, Identica, Fark, Linkagogo, Faves, WordPress, GetGlue, Bebo, and Blogger.
The plugin gives you the choice to either include or exclude link buttons for any of the available services. The best approach is to offer between 8 and 12 share buttons; any more tends to clutter your pages.
The download link is at http://wordpress.org/extend/plugins/share-and-follow/. There is a video on the download page that shows you how to install and set up the plugin.