Actually Microsoft does "oversee" the company that they bought(acompli) First like of the Eula is "we collect and process your email address and credentials, carry out transactions that you authorize. We may access,disclose and preserve your personal information including private content such as content of your emails ,other private communications or files in private folders.
As much as Microsoft "oversees" acompli, I still don't trust it. Especially when it spells out that it will keep your private info and share content of emails.
End user license agreements are a very telling thing. Those and "privacy statements". I have sensitive info to protect. I don't need another company combing though business that includes non public personal info of mine or of my clients as well. New to the iPhone I may be, but not to security.