The zooComment (by Yootheme) module allows to choose from several different themes in the module's options: bubble-angled-h, bubble-angled-v etc.
This update adds the theme: bubble-popup which only shows the avatars, and pops up the message smoothly when you hover over them.
This bubble-popup started from a copy of bubble-angled-h; main changes are in the css, to make bubbles' position absolute, and hiding them; and in the bubble-popup.php, where jQuery is used to add behaviour.
To use, simply extract the contents of the archive to the root of your Joomla! directory, no files will be overwritten, and the new files:
will be copied. Now you can go in the module's configuration and choose the "bubble-popup" template.