H. Peter Pfeufer

Add a sidebarwidget to display the count of your twitterfollowers, your googleplus circles, fans of your facebook-fanpage, and your feedreaders (from feedburner) in your sidebar.
Features
<ul>
<li>Easy install</li>
<li>Panel for easy configuration</li>
<li>No external scripts</li>
<li>Cleaning up database on uninstall</li>
</ul>
Languages
<ul>
<li>German</li>
<li>English</li>
</ul>

Social Impact Widget

aitor.delapuente

This plugin helps ensure your content has a relevant thumbnail when shared on social sites.
Adds an image_src and og:image meta tags to your header using post thumbnnail (you must have post thumbnails / featured image enabled), first image on post/page content, or a defined default image.

FetenWeb image_src Metatag

This plugin helps ensure your content has a relevant thumbnail when shared on social sites.

Social Impact Widget vs FetenWeb image_src Metatag