Dimox

Plugin replaces comment author link and (or) links in comment text on jQuery links that will work (i.e. it will be possible to go on the specified site through these links) only in case when the JavaScript technology is enabled in a browser of the visitor of your site.
When can this plugin might be useful:
<ul>
<li>If you want to reduce the number of external links on your site (for example, for any SEO reasons).</li>
<li>If you don’t want to refer to bad sites and you don’t have time and desire to check the links, which are left by the authors of comments.</li>
</ul>
Here is how it looks. For example, there is such a link on the name of comment author:
<pre><code><a href='http://sitename.com' rel='external nofollow' class='url'>Comment Author Name</a>
</code></pre>
After plugin activation this link will turn to the such:
<pre><code><a href="#" class="jqcl" title="sitename.com" rel="nofollow">Comment Author Name</a>
</code></pre>
This is jQuery link, that will work only if JavaScript technology is enabled in a browser of the visitor of your site.
Links to your site will not be replaced.

jQuery Comment Links

Plugin replaces comment author link and (or) links in comment text on jQuery links.

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.

jQuery Comment Links vs WordPress Social Login