I believe this is one step in transitioning away from 'pages' to something more like apps, where they load and you interact with them through UI and state inste

I believe this is one step in transitioning away from 'pages' to something more like apps, where they load and you interact with them through UI and state instead of links. They've already made it basically a requirement to have JavaScript enabled on their sites (for instance Google + is just a blank page without JS), and if you read the Dart leaked memo they seem deathly afraid of smartphone/tablet apps. Seems believable to me anyway... for instance I read mail almost entirely on my phone now and never log into the gmail.com. Since I'm not using their mail app I never see their ads.