axenso

You can enable a tooltip that shows info about user/author when you rollover/click on related avatar.
Let’s speak clearly: if you are loooking for a plugin that enables the standard Gravatar hovercards, this is not the plugin right for you. Please look for another one.
When you rollover/click on an avatar (e.g. of a comment author), a tooltip popups and shows:
<ul>
<li>some additional links if the author is a registered user: e.g. to user post archive, to user external website, to user blog (if multisite)</li>
<li>some info from Gravatar if author is registered to that service: e.g. location, “about me” description, websites, other account pages (facebook, twitter….)</li>
</ul>
In plugin settings you can set up the javascript and css main options.
The plugin comes with some filter hooks, so you can customise the tooltip content at all.
The plugin uses <a href="http://craigsworks.com/projects/qtip2/" rel="nofollow ugc">qTip plugin for jQuery</a>.

Avatar Tooltip

To show a tooltip with info (member info and Gravatar profile) when you mouseover/click on an avatar.

CeiKay

Tooltip CK
Example of use :
{tooltip}Text to hover{end-texte}a friendly little boy{end-tooltip}
Get more informations and see the demo on https://www.ceikay.com/plugins/tooltip-ck
<h3>Features</h3>
<ul>
<li>Styling from the plugin settings interface with color pickers and other fields</li>
<li>Open with animation</li>
<li>Options for the tooltip position (top, bottom, left, right)</li>
<li>Options for the tooltip animation duration, delay before hide</li>
<li>Options to style the shutter text (text to mouseover)</li>
<li>Mobile/Touch Device compatibility</li>
<li>Screen overflow detection</li>
<li>Editor button for a fast tooltip creation</li>
<li>Custom settings for each tooltip : content, width, duration, delay</li>
<li>Compatible multilanguage with the POT file</li>
<li>French translation included</li>
</ul>

Tooltip CK

Tooltip CK allows you to put some nice tooltip effects into your content.

Avatar Tooltip vs Tooltip CK