Personalize, if not humanize, your posts, adding (CSS) popups containings avatars next to mailto links, as well as next to any word. You can chose avatar images, or let Gravatar chose it for you.
For documentation and tips, please refer to the official plugin page for <a href="http://planetozh.com/blog/my-projects/wordpress-plugin-avatar-gravatar-popup/" title="Avatar Popup" rel="nofollow ugc">Avatar Popup</a>

Ozh' Avatar Popup

Add CSS popups next to mailto links or next to any word. Can be any custom image, and has gravatar support.

Boone Gorges

<a href="http://yourls.org/" title="Your Own URL Shortener" rel="nofollow ugc">YOURLS</a> is a free URL shortener service you can run on your webhost to have your own personal Bitly.
This plugin is a bridge between <a href="http://yourls.org/" title="Your Own URL Shortener" rel="nofollow ugc">YOURLS</a> and your blog: when you’ll submit a new post or page, your blog will tap into YOURLS to generate a short URL for it.
This plugin also features BuddyPress support. Short URLs can be generated automatically for each member and each group, and are customizable if permitted by the BuddyPress administrator.
Requires PHP 5.
Note: this plugin should still work but is no longer maintained. See http://yourls.org/#More#wordpress

YOURLS: WordPress to Twitter

Use YOURLS (a free GPL URL shortener service) to create short URLs of your posts, or for your BuddyPress groups and users

Ozh' Avatar Popup vs YOURLS: WordPress to Twitter