People have asked about which tools/languages we use. We use Flash 9/Flex on our client. Our server is Linux, Apache, MySQL and Python. Given our Microsoft systems backgrounds (Darrin and I worked on OS/2 and NT back in the day), this has been a fun and interesting experience.
It’s amazingly responsive, and, from reading the blog associated with it, it’s all only running on one server at the moment… very nicely done.