brehash

This plugin adds the official <a href="http://blog.twitter.com/2010/08/pushing-our-tweet-button.html" rel="nofollow ugc">Tweet Button</a> from Twitter to your Pages, Posts or Home Page. It lets your users share links directly from the page they’re on. When they click on the Tweet Button, a Tweet box will appear pre-populated with a shortened link that points to the item that they’re sharing.
This plugin is very customizable via ‘rsh-Tweet Button’ under the ‘Settings’ menu in WordPress Admin. Change the look and feel, pozition and where to seen of the button.

rsh-Tweet

Adds the official Tweet Button from Twitter.com.

rohanpawale

<a href="http://techlunatic.com" rel="nofollow ugc">Author Site</a>| 
<a href="http://techlunatic.com/2011/08/social-share-elite-wordpress-plugin/" rel="nofollow ugc">Plugin Home Page</a>
This plugin is the most efficient way to integrate the important social share buttons like twitter, facebook like, google +1 (plus one), LinkedIn and stumbleupon in three different position and styles.
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Automatically display the social share buttons Above the post, below the post, both above and below or floating left side of post.
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Flat/Round border style with/without background color. All easily configurable through settings.
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Javascript is by default loaded in footer (recommended). This is the most efficient way to load scripts for social share buttons. This will make sure that your site contents are loaded first and the script loading do not interfere with them. Also site loading speed is better by doing so which is an important criteria for SEO. 
Option to load the script in header as well, if you wish to.
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Left side floating option is the latest trend these days. The top and left spacing can be configured according to your site layout. Using simple CSS and not ajax for better performance. Also floating bar can be fixed on that position or absolute and can be configured easily through settings.
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Option to display on home page, static pages, category, tag, archive pages.
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Shortcode [sse_social_share] which can be inserted in test for any post or pages to display the socail share bar.
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Add a custom field “disable_social_share” with value “yes” to disable social share for specific pages or posts.
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Facebook Like thumbnail will now display thumbnail specific to the post or page.
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Adjust width of individual social share button configure count display.
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Option to manually display the share box at any position.
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Support for buffer app included
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Social Share Elite

Get the most advanced solution for social media integration for your business blog and make the most of your online presence.

rsh-Tweet vs Social Share Elite