Media-contextual banners are currently undergoing beta testing.
Impression statistics can help you evaluate how effective your banners are. You can view ad campaign reports after your ads start displaying. To view this data, go to the Reports Wizard.
For example, you can see the queries that triggered your ads. Under Sections, choose Banner number and Search query, and under Columns, choose Clicks and Bounces. To prevent Yandex.Direct from serving ads for non-relevant searches, use negative keywords. You can add them on the page where you edit your campaign or banner group.
Read more information about campaign statistics.