PResponsive

This plugin will add a image below your posts, allowing your visitors to share your posts with their friends, on FaceBook, Pinterest, Google+, Twitter, Myspace, Friendfeed, Technorati, del.icio.us, Digg, Google, StumbleUpon, and other. After plugin is activated a buttons will appear after the content of the post.Clicking this button will bring the user to the bookmarking site. If the user isn’t logged in they will be prompted to do so. 
Post your articles to the social bookmarking sites and get traffic.

WP Social Bookmarking

WP Social Bookmarking plugin syndicates your blog posts in social networking sites.

vfvalent

The Social Bookmarking RELOADED 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 in a number of social bookmarking sites. 
Furthermore, the plugin adds a page in the WordPress admin section that lets you customize it.
Social Bookmarking RELOADED support the list below: 
The following sites are supported: Del.icio.us, digg, FURL, blinklist, Socializer, reddit, Feed Me Links!, Technorati, Newsvine, Ma.gnolia, Google Bookmarks, GOOGLE BUZZ, Squidoo, BlinkBits, Stumble Upon, Netvouz, Rojo, Blogmarks, Co.mments, Scuttle, Tailrank, Bloglines, Segnalo, OkNotizie, Netscape, Bookmark.it, Ask, linkagogo, del.irio.us, Socialdust, Live MSN, Slashdot, Sphinn, Diggita, FaceBook, Upnews, Wikio, Barrapunto, Notizieflash, Fai informazione, Blogmemes, Blogsphere news, Blogsvine, Scoopeo, Myspace, ZicZac, Twitter, IndianPad, Technotizie, Blue Dot, Connotea, Diggitsport, Tipd, FriendFeed, digo, buzz.
In plugin .zip file, there is a pdf file about installation, usage of Social Bookmarking Reloaded in english, italian and spanish. 
You can see the video how social bookmarking reloaded works on <a href="http://www.savevideos.net/" rel="nofollow ugc">Save Video</a>.
<h3>Others</h3>
Update Instructions (from version RELOADED 1.8) – Aggiornamento del plugin (a partire dalla versione 1.8) 
Upload all the contents of the social-bookmarking-reloaded directory to your wp-content/plugins/social-bookmarking-reloaded directory. 
Delete the folder social-bookmarks-reloaded. 
Than activate the plugin in plugin menu of control panel. 
If your blog is based on WordPress 2.5 and newer, you can use automatic update in plugin panel.
If you would like to submit an useful social, that is not included in this plugin, important please send me an 18×18 icon and a link for submition e.g. www.soc ial.xz/submit?url={link}&title={title}. To do this, you can add a comment in a social bookmarking reloaded post. Thank you very much.
Send me the material I have mentioned before, otherwise I will ignore your request of inclusion. (I will not register every social request I receive.)
For social bookmarking RELOADED: valent 
http://www.valent-blog.eu
Based on GNU GPL plugin: 
Social Bookmarks 3.2

Social Bookmarking RELOADED

The Social Bookmarking RELOADED plugin for WordPress adds a list of XHTML compliant graphic links at the end of your posts and/or pages that allow you …

WP Social Bookmarking vs Social Bookmarking RELOADED