Tooltip let's you create mouse over tooltips to your content and allows you to show additional information.It using Gzip loader technique that will deliver CSS and Javascript files more faster and also with minimun HTTP request.Need MooTools,PHP and a few js.The main code is from YOOtooltip.

There's a lot of powerful interactivity you can bring to your site using javascript besides slick navigation menus.This plugin of mootools is like tooltip.It's have a pretty cool effect!This example is come from http://nettuts.com/.