Hotmail, SkyDrive privacy

Microsoft identified a former employee as the source of some press leaks of software under development (among others,  Windows 8).
Micorsoft did so by searching the hotmail and Skydrive data of the journalist and the employee.
This is remarkable, as Microsoft launched the Scroogled campaign site against Google guaranteeing: Outlook.com is different—we don't go through your email to sell ads.
According to the terms of service of its Communication Services Microsoft has every right to go through your data:
Microsoft reserves the right to review materials posted to the Communication Services and to remove any materials in its sole discretion.
So, the terms of service do not include the campaign assurance that Microsoft will not go through your data for specific goals like selling ads, they may do so whenever they feel like it.
They do include motives that may trigger the of your data in the terms of service:
Microsoft may access, disclose, or preserve information associated with your use of the services ... [to] protect the rights or property of Microsoft or our customers.
So anything that has to do with licensing of software, music etc. may cause your data to be searched and any legal claim by a Microsoft customer (that's the entire business world) may lead to data disclosure.
Indeed, in the campaign, Microsoft does not claim that they will not go through your email. They just don't go through it with the purpose of selling adds.