No AdSense optimisation at all; barely touched the account. The most sophisticated it gets is that it's using the async code (which we got access to quite early on), and there's a bit of conditional logic which fires to determine which size to serve based on the viewport width. Love to hear any ideas you have - though AdSense is really a temporary cost covering measure while we grow the email database, develop the app, etc. We'll bin it when we're large enough to move reliably to other methods.