Google announced they are rolling out Matched Content ads units, which they began testing last year. Google said:
Starting today, you can use Matched content units to directly generate revenue by allowing ads to appear alongside your recommended content.
With the new “Allow ads” feature, relevant ads will appear within your Matched content units, and will be styled to complement the look and feel of your content recommendations. We’ll gradually roll this feature out to all Matched content eligible publishers across the globe over the coming weeks. To enable ads, visit your My ads tab and choose “Allow ads” for your Matched content units.
Here is what they look like:
To check whether your website is eligible for Google Adsense Matched Content, Just login to your adsense account now.