ichurakov

The Open Graph protocol enables any web page to become a rich object in a social graph. For instance, this is used on Facebook to allow any web page to have the same functionality as any other object on Facebook.
To turn your posts and pages into graph objects, the plugin add the following metadata to webpage header: 
og:title – The title of your post/page. 
og:description – The excerpt of your post/page. 
og:image – URL of featured image (if exists) which represent your post/page. 
og:site_name – The title of website. 
og:url – The canonical URL of your post/page.
Plugin support page: <a href="http://www.icprojects.net/open-graph-meta.html" rel="nofollow ugc">Open Graph Meta</a>.

Open Graph Meta

This plugin add Open Graph meta data to blog posts and pages.

akurganow

Plugin insert open graph metadata on your WordPress site. The plugin still in beta, so please send bug reports to me by <a href="mailto:akurganow@polzo.ru?subject=ogMeta" rel="nofollow ugc">e-mail</a>. If you want to help with the translation, write to the same e-mail, but with the notation “Translation [language]”
<ul>
<li>More information: <a href="http://polzo.ru/ogmeta" rel="nofollow ugc">Polzo.ru</a></li>
<li>See: <a href="http://ogp.me/" rel="nofollow ugc">OPG.me</a></li>
</ul>

Polzo ogMeta

Plugin insert open graph metadata on your WordPress site.

Open Graph Meta vs Polzo ogMeta