Mountain Lion offers a new feature called Power Nap, but since it’s limited to only a few recent laptop Mac models, most people probably haven’t seen it. In short, Power Nap enables supported Macs to wake up briefly to back up via Time Machine, check for email via Mail, receive new messages in Messages, and update iCloud-related data, including calendar events, contacts, reminders, notes, iCloud documents, and photos in Photo Stream. Over at Macworld, our friend Dan Frakes explains just what Power Nap can do, how you use it, why it works on so few models, and more. follow link
Wake On Demand in Snow Leopard
Putting your Mac to sleep saves power, but it also disrupts using your Mac as a file server, among other purposes. Wake on Demand in Snow Leopard works in conjunction with an Apple base station to continue announcing Bonjour services that the sleeping computer offers.
While the requirements for this feature are complex, eligible users can toggle this feature in the Energy Saver preference pane. It's labeled Wake on Network Access for computers that can be roused either via Wi-Fi or Ethernet; Wake on Ethernet Network Access or Wake on AirPort Network Access for wired- or wireless-only machines, respectively. Uncheck the box to disable this feature.
Dan Frakes Explains Power Nap