I'm sure they use a CDN for delivery of the flash assets. The flash is still most likely updated several times a day. We used to batch commands in the client

I'm sure they use a CDN for delivery of the flash assets. The flash is still most likely updated several times a day. We used to batch commands in the client and submit every 6 seconds. It was still a crazy number of writes, because basically every click is a database update. MySQL is really bad at that sort of work load, but I migrated almost everything to Redis. Really fun problems to solve!