This isn't an ad play at all. It's an attempt to build features into the browser that help people find new contextually relevant web sites. Say you're on YouTube watching a video. Where are the outbound links? How do you get to other sites that are embedding or linking to the video to see what they have to say? Today you can't because YouTube wants to keep you in YouTube. But what if your browser could tell you about related sites so you could escape YouTube and find great contextually relevant content out on the Open Web? Wouldn't that be nice? Nothing to do with advertising at all.