Lopo Lencastre de Almeida

Automatically add links to your favorite social bookmarking site on your posts, pages and in your RSS feed. WordPress 2.6 or above and Sociable 3.4.1 or above is required, if you use an older version of those, please upgrade.
More info:
<ul>
<li>More info on <a href="http://yoast.com/wordpress/sociable/" rel="nofollow ugc">Sociable</a>, with info on how to add sites to it, and how to integrate it into your WordPress in other ways.</li>
<li>Check out the other <a href="https://wordpress.org/extend/plugins/profile/ipublicis" rel="ugc">WordPress plugins</a> by the same author.</li>
<li>Also at <a href="http://box.net/iPublicis4Wordpress" rel="nofollow ugc">iPublicis4Wordpress</a>.</li>
</ul>

DoMelhor for Sociable

Automatically add links on your posts, pages and RSS feed to your favorite social bookmarking sites. Requires Sociable 3.4.1 or above.

utahta

This plugin inserts social share links at the top or bottom of each post. 
For theme developers, social share links can be added by PHP code or by using shortcode. Check documentation for this use-case.
This plugin documentation can be found <a href="https://github.com/utahta/WP-Social-Bookmarking-Light/wiki" rel="nofollow ugc">here</a>.
This is the list of used social sites:
<ul>
<li>Hatena</li>
<li>Facebook Like Button</li>
<li>Facebook Share Button</li>
<li>Facebook Send Button</li>
<li>Twitter</li>
<li>Tumblr</li>
<li>Google Bookmark</li>
<li>Google +1</li>
<li>Delicious</li>
<li>Digg</li>
<li>reddit</li>
<li>LinkedIn</li>
<li>Instapaper</li>
<li>StumbleUpon</li>
<li>mixi Check</li>
<li>mixi Like</li>
<li>GREE Social Feedback</li>
<li>atode (toread)</li>
<li>LINE</li>
<li>Pocket</li>
<li>Pinterest</li>
</ul>

WP Social Bookmarking Light

This plugin inserts social share links at the top or bottom of each post.

DoMelhor for Sociable vs WP Social Bookmarking Light