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.

3hmedia

WP LikeJS includes a nice jQuery driven Like Box Popup Box onto your Website or Blog, which pops up when the user is scrolling your page down. You can choose how much px have to be scrolled before the LikeJS Box is displayed. 
Also you can change the headline of the Box for your communication with your visitors like “Follow us on Facebook” or whatever you want. 
The script is very smart and loads fast and is compatible with all mayor browsers.
Demo: http://www.like-js.de

WP LikeJS

WP LikeJS includes an eyecatching Facebook Like Box on your website. You'll get more Fans with LikeJS than with an usual Like Button and it locks …

Fastershare vs WP LikeJS