"New! See where your ads appeared on the Content Network. View site-by-site metrics, optimize your performance on content pages, and gain greater transparency into your campaign with the Placement Performance Report. "
The placement performance report has appeared only in some of my clients accounts. I suspect it is a slow roll out.
Keep in mind that it is really only useful if you have and trust the Google conversion tracking. Without the conversion tracking, you will only know where your ads are displayed, which is only part of the whole picture. You ultimately need to know what the ad clicker did once they arrived at your site.
Some log analysis tools have been doing this type of report for sometime. Basically, I think they filter the logs on referrals from the googlesyndication.com domain.