many Social Bookmarking plugins available for WordPress here Top 16 Social Plugins For WordPress
Lifestream displays your social feeds and photos much like you would see it on many of the social networking sites.
Social Bookmarking RELOADED – Add the social bookmarks services’s icons to your articles in your blogs in order to submit them easily.
Displays all of your online identities (Twitter, Facebook, Flickr, LinkedIn, YouTube, more) as clickable links in your sidebar.
ShareThis plugin allows users to add your post to many social bookmarking sites, or to send your post link via email, AIM, Facebook, MySpace and more.
BuddyPress is a suite of WordPress MU social networking plugins and themes.
Automatically add links on your posts, pages and RSS feed to your favorite social bookmarking sites. WordPress 2.6 or above required!
The AddThis Social Bookmarking Widget allows any visitor to bookmark and share your site easily with many popular services.
This plugin allows you to automatically post your new posts on the twitter website.
Create a social community using Google Friend Connect. Easily add many different gadgets.
**obsocialbookmarker** is a social bookmarking plugin which adds user-submission links at the bottom of each post for various social bookmarking sites
Adds a “Tweet This Post” link to every post and page, so your readers can share your blog entries on their Twitter accounts with ease. Short
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.
Automatically add links on your posts to popular social bookmarking sites.
Adds a ‘Share This Post’ button after each post. The share botton supports e-mail address book, social bookmarks and favorites.
I Love Social Bookmarking is a simple WordPress plugin that allows your readers to submit your content to social media services
Gregarious is the ultimate social bookmarking plugin. Everything is configurable. Share link, Digg button, stats, FeedFlare, LiveSearch and more.