Microsoft Research and researchers at UC San Diego developed a new method to save on power in sleep mode while still keeping up with IMs and whatever other network activity you might be up to.
Dubbed "Somniloquy," the USB dongle acts as an external networking card, and takes over most of the communication duties, with its own embedded OS and flash memory. When the computer goes to sleep, Somniloquy maintains IM connections, ongoing downloads and torrents, and keeps your computer present on the local network and wireless LAN. If an activity arrives that needs the full computer, Somniloquy wakes up the computer and patches it through.
Somniloquy boasts up to 60 to 80 percent overall energy savings based on the person’s usage habits.