Microsoft has begun testing the Microsoft Content Ads Beta. Currently, it is only a limited beta. Microsoft Content Ads Beta program allows an advertiser to place ads in the content network. The added feature is under "Targeting". You can select a language and a region for the ad group. It also allows you to select a distribution method for the ad group. You can check off "Search" or "Content" or even both of them.
Microsoft explains all about Contextual Advertising here.