Hi Nima,
The package used is the Ajax Helper package and it's currently on OpenACS head. It's nothing fancy really, it just generates the javascript that you can embed into your templates or include in your tcl code.
http://cvs.openacs.org/cvs/openacs-4/packages/ajaxhelper/
The javascripts are from the Prototype and Scriptaculous javscript libraries. They allow you to do cinematic effects and make ajax calls. You'll see some of the effects on the demo.
The ajax part of the demo is that (at least of admins right now) when the portals are rearranged an xmlhttp call is made to a url that receives the new sorting order and updates the database accordingly so that positions of the portlets will persist.
This will probably need a lot of work for it to be at par with Netvibes or Google home pages (http://www.google.com/ig) but I consider this a proof of concept that an incredible toolkit like OpenACS with a robust backend can also have an incredible front end user interface that can ellicit "wows" and "ooohs" from it's users.
http://sgsandbox.com:8002/xowiki/demo
User : mailto:demo@solutiongrove.com
Pass : demo
Best,
Hamilton
