Alan sez, "Microsoft is pushing out an update to its privacy policies."
Featured prominently on the front page is a promise not to use the content of personal emails (presumably those emails sent or received through Microsoft mail services) for ad targeting.
This sets Microsoft distinctly apart from other companies, notably Google, who explicitly do read the contents of your emails in order to target you with ads.
This is effectively the same regime that Gmail users who use Google's official email encryption tool will get — targeting based on social graph, search history and browsing history, but not email contents.
Microsoft Services Agreement FAQ
(Thanks, Alan!)