I've worked with numerous retailers who use something like this. Usually an eMail server just makes a ping when a payment notification comes in.<p>During peak seasons (read: December) at an ecommerce company of mine a few years ago, we did pretty much exactly this. We used a cash register sound, though. Played it into the office and warehouse so everybody knew how fast things needed to be going. Totally worked, the faster the register went, the harder everyone worked.