By default email is not encrypted...
One of the big reasons not sending documents through hotmail or another service doesn't seem to be the case anymore.
5. Your content
Except for material that we license to you, we don't claim ownership of the content you provide on the service. Your content remains your content. We also don't control, verify, or endorse the content that you and others make available on the service.
Maybe this was just one of those old rumor things but I seem to recall this not being the case. Where Microsoft used to claim in their EULA that they owned the content you put up on their service.
I don't care for anything "cloud" based as there is always a chance of accidents happening. (Or ICE will decide they want to raid your data)