In short its a nifty way to get round firewall issues on certain hosts.
Detailed Explanation here:
http://www.greycube.com/site/forum_viewtopic.php?3.1535
I currently have it being demonstrated on the right. It looks and works exactly like a regular LGSL, except instead of getting the information directly from the server, its using a copy of LGSL running on my greycube.net test site 🙂