FogCreek just launched Trello.

Now if you try to Google what technology they are using you will see a Stackoverflow post that has been deleted. I am sure its because of some community violation (like it should be on Meta Wiki).

Anyway its not hard to figure out (firebug) that they are using a Nodejs stack:

• Nodejs for Webserver
• Express for MVC
• JQuery
• Backbone
• SocketIO
• JQueryUI

Now the only question is what data storage they are using. I’m going to guess that they are probably using MongoDB for regular structured fields and maybe Redis for some of the communication and MOM.