This plugin adds the Retaggr functionality to your blog.
** IDENTITY **
The Retaggr Profile Card is about identity – its a virtual, interactive business card which you can customize as you wish. 
Widgets can be added into it to show posts from your blog,music you’re currently listening to, allow communication via IM, or pretty much 
Consolidate all your identity widgets on your blog into one, and add custom widgets from anywhere on the web. Built-in widgets include support for Twitter, FriendFeed, Flickr, MSN, and Disqus, to name a just a few.
People use Retaggr Profile Cards to bring traffic to their blog and express their identity. A demo can be found at retaggr.com.
Installing this plugin means :
<ul>
<li>Your visitors can leave their retaggr card when they comment on your posts</li>
<li>When referring to other people in a post, you can insert their profile card, instead of just linking to their blog. </li>
<li>Your card is attached to your posts</li>
</ul>
These unintrusive enhancements add context to your posts – bringing fun and useful functionality to your site, while keeping readers from unnecessarily navigating away to find out more about the person in question.
retaggr also allows you to add site specific widgets to card on your site – explore retaggr.com for more details.
** IMAGE TAGGING **
This plugin also gives your blog powerful image tagging functionality. Your users can tag people in any image on your blog, much like you would on a social network. 
Just drag around the person in the image and select the name from your address book, which is integrated with your email or Facebook. 
Mousing over the person then shows their retaggr Profile Card. There are full moderation and notification options.
You do not need to modify any of your template files — just activate the plugin, and set your options on retaggr.com.
<h3>Feedback/ Help</h3>
Don’t hesitate to drop us a line via the retaggr.com website if you need anything at all.

retaggr

This plugin adds the Retaggr functionality to your blog.

Rodrigo Primo

A simple plugin that adds the required meta tags to allow you to use your blog URL as your OpenID identifier with the provider you choose.
This plugins does not allow you to use your WordPress installation as a OpenID consumer or provider.
It was built based on MyOpenID Delegation plugin (https://github.com/benatkin/wordpress-myopenid-delegation).

OpenID Delegation

A simple plugin that adds the required meta tags to allow you to use your blog URL as your OpenID identifier with the provider you choose.

retaggr vs OpenID Delegation