A patent filed by Apple has recently been published for public viewing. This one talks about a sleep proxy for services over a network. Just what does that mean? Well, check out the wording from the filing:
One embodiment of the present invention provides a system for implementing a sleep proxy. The system starts by receiving a request at the sleep proxy for information pertaining to a service provided by a device. In response to this request, the system determines if the device is a member of a list of devices for which the sleep proxy takes action. If so, the system determines if the sleep proxy can answer the request. If so, the sleep proxy sends a response to the request on behalf of the device. In a variation on this embodiment, if the system cannot answer the request on behalf of the device, the system sends a wakeup packet to the device, wherein the wakeup packet causes the device to exit a power-saving mode so that the device can respond to the request directly.
Basically, you can sleep or wake computers over a server. The feature seems to relate to Wake on Demand, which lets users do things such as screen sharing over an Airport network and Snow Leopard. They can even wake other computers even if the other machine is asleep…that's where Wake on Demand comes in. Here's some more info on that: Wake on Demand