andeggs

ProSocial is a free WordPress plugin which connects your readers with your authors.
It shows an attractive pop-up bar next to your authors’ names, with links to their social media accounts.
On multi-author blogs, it’s a great way of encouraging your readers to connect with your authors on other social networks.
See it in action here: http://digitalshift.me/prosocial/
Features:
<ul>
<li>40+ social networks: You choose which networks to display. Your authors can add then their accounts themselves.</li>
<li>Includes email: Show your authors’ email addresses as well (with a captcha form to prevent spam).</li>
<li>Google Analytics: If you use Google Analytics, you can see who’s clicking on what.</li>
</ul>

ProSocial

ProSocial shows a pop-up bar next to your authors' names, with links to their social media accounts.

alexpooley

Selectively add social network buttons such as digg, sphinn, etc to your posts or theme design.
I wrote this plugin because I wanted finer control over where and which buttons 
were placed on my site and in my posts.
Sometimes I have marketing posts so I want to link to Sphinn, but sometimes I have 
technical posts so Reddit would be a better choice. This plugin is flexible enough that 
if you want the same button in every post, then you can still modify your theme very easily 
to accomplish this.
You may place as many buttons, in as many places in your posts as you like.
This plugin handles: 
– Digg 
– Reddit (all button styles) 
– Delicious 
– Sphinn 
– Dzone (all button styles) 
– StumbleUpon
<h4>For Your Posts</h4>
Use the following in your posts: [SB button 1, …, button N]
Here’s an example post…
<pre><code>Hey, check out my new buttons!
Here they are: [SB digg, delicious, reddit]
And look
Here's some more:
</code></pre>
 [SB reddit, sphinn]
The different button types are: 
– digg 
– delicious 
– reddit 
– reddit1 (same as reddit) 
– reddit2 
– reddit3 
– sphinn 
– dzone 
– dzone1 (same as dzone) 
– dzone2 
– stumbleupon 
– stumble (same as stumbleupon)
<h4>For Your Themes</h4>
<pre><code><?php echo sb_make_button('digg', 'http://www.alexpooley.com') ?>
<?php echo 'I'm in a post now:'.sb_make_button('reddit', get_permalink()) ?>
</code></pre>

Social Buttons

Selectively add social network buttons to your posts, or theme design.

ProSocial vs Social Buttons