But really, "hibernating" is what our PocketPCs are currently doing now when you press the power button or power off. I'm sure that aspect of it will remain the same, so that you have instant accessibility to your data whenever you turn it on..... as opposed to waiting on it to load the OS. For the "everyday" use of a PDA, this is what you would be wanting to use. However, I hope they include a TRUE power-off function for those times when you know you won't be touching the device for a day or two.... so that the battery doesn't get drained.
For example, I usually just close the lid of my laptop (sleep mode) if I'm just leaving it unused for an hour or so. But if I'm gone longer than that, I'll usually power it off to keep the battery from draining due to the data still being stored in RAM.
So I've got my fingers crossed that this will be a feature.
