Earlier this week, Microsoft's adCenter launched a contextual ad network, Content Ads. Two new adCenter features allow advertisers greater control in ad placement.
Website exclusion does exactly what the name implies. If you don't want your ad to appear on a specific website, this feature prevents it from doing so. Do this by clicking "edit" in the ad group settings when modifying a campaign.
Site performance reports enable advertisers to view how their Content Ads are performing on a given website. You can run the report by clicking on the reports tab and clicking on "Site performance" under basic settings. From there, you can select account, view, and date range. Reports can be downloaded, if you so desire.
Obviously, these two features work hand-in-hand. Use the site performance report to see which sites perform best for your ad campaign, and then add the poorly performing ones to the Website Exclusion list.
The features are only available in the browser version currently - and also only available in the U.S. The desktop version of adCenter will get these features in a future release.