Miled

WordPress Social Login allow your website readers and customers to register on using their existing social accounts IDs, eliminating the need to fill out registration forms and remember usernames and passwords.
WordPress Social Login also allow you to import users contact list from Google Gmail, Facebook, Windows Live and LinkedIn.
WordPress Social Login gives you absolute control over users access to your website and comes a list of rules and restrictions for you to setup.
Easy to customize and integrate 
Wordpress Social Login come with a simple but flexible and fully customizable authentication widget. And if you are a developer or designer then you can customize it to your heart’s content.
Wide variety of providers 
Depending on the audience you’re targeting, you can choose from a wide variety of providers and services including: Social networks, Microblogging platforms, Professional networks, Media, Photo sharing, Programmers and Gamers networks.
Currently supported providers 
Facebook, Google, Twitter, Windows Live, Yahoo!, LinkedIn, Reddit, Disqus, Tumblr, Stackoverflow, GitHub, Dribbble, Instagram, 500px, Foursquare, Steam, Twitch.tv, Mixi, Vkontakte, Mail.ru, Yandex, Odnoklassniki, Goodreads, Skyrock, Last.fm, AOL and PixelPin.
Free, unlimited and white-label 
Wordpress Social Login is open-source and completely free. The source code is publicly available on <a href="https://github.com/hybridauth/WordPress-Social-Login" rel="nofollow ugc">GitHub</a> for anyone to help and contribute. You are free to use a WordPress Social Login in commercial projects as long as the copyright header is left intact.
Big thanks to everyone who have contributed to WordPress Social Login by submitting Patches, Ideas, Reviews and by Helping in the support forum.

WordPress Social Login

WordPress Social Login allow your visitors to comment and login with social networks such as Twitter, Facebook, Google, Yahoo and more.

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.

WordPress Social Login vs Social Buttons