Google has long been on the cutting edge of publisher monetization solutions and it's taking it all a step further by launching AdSense Labs, a new feature (a subtab under the Optimization tab within AdSense accounts) where publishers will find some rather interesting "experimental" features.
The first two "Labs" that Google is launching are...
Show Fewer Ads : The new Show Fewer Ads feature essentials reduces the number of ads shown to users in exchange for a negligible drop in your revenue. It aims to remove at least 10% of the ads served on a site (1% or less of your revenue), by preventing low value ads from being shown to users.
Inline Ads : The new Inline Ads Lab are 320x100 ad units which are automatically inserted within a mobile site as a user scrolls down the page. Google suggested that with this new ad format publishers will no longer need to write the logic to dynamically insert ad units on a page, leaving the technical modifications up to Google instead.
Keep in mind that not all features are suitable for every site so they may not appear within specific individual accounts. Also keep in mind that these are experimental features and are meant to really expose to Adsense publishers what Google is working on and let publishers provide some feedback along the way.