See this page for the specific text you can include to describe your Display Ads
Well - because it is the law, for one, but also...
Many of our partners require this to be in place in order to participate in your auction, so not only is a good idea from a business perspective, but it will also impact your revenue as well.
In the meantime, please put the Mediavine-required text up while you are working on the rest.
Click Update Settings, and you are done!