danielfaerber

If you install this plugin on your blog, your visitors get two buttons below your posts and pages:
<ul>
<li>A Facebook “share” button</li>
<li>and a Twitter “tweet” button.</li>
</ul>
These are not the standard Like- and Tweet-Buttons, which also display how many people have clicked on it so far, but basically pure and simple html-links.
DISADVANTAGE:
<ul>
<li>Less interaction.</li>
</ul>
ADVANTAGES:
<ul>
<li>It’s faster. Your blog does not have to contact Facebook’s and Twitter’s servers.</li>
<li>Better privacy. No information about your visitors is sent to Facebook or Twitter. Nota bene: Facebook’s standard like button allows Facebook to track your visitors even if they do not click on it!</li>
</ul>

Fastershare

This plugin allows your visitors to share your posts on Facebook and Twitter, without JavaScript or iFrames.

Alex Sawallich

This plugins enables the famous Google +1-button in your wordpress-installation. The button is shown beneath 
your posts/pages. With this button you can share the permalink to your post/page in your Google+ profile.
You’ve got the possibility to change the look of the button in the same manner, that you can do by using the 
configurator that Google provides: see <a href="http://www.google.com/webmasters/+1/button/" rel="nofollow ugc">Google plus one</a>.

Google+ One Button

Provides a +1 button from Google+ beneath each post/page.

Fastershare vs Google+ One Button