Personally I find most of the value is in the content and not the layout. So it's not really anything like view source which mixes them and makes it very difficult to read the content.
Of course it's a bit different with full blown web apps but I can't think of any web app I use that is supported by advertising.
> If the sites 'content' is loaded with JS rather than being visible in the static source, there is not going to be much you can do.
The problem is now two-fold: 1) You are going to hurt your search rankings, and 2) it is possible for ad blockers to get around. Like I said just get the browser to load and run the js, ads, etc, and just not render anything that's not clearly content.
Ad driven sites could up the game by requiring user interaction before they load the content, but if the interaction is simple and repeatable then its easy to tag and handle.
They could start requiring captchas etc that are integrated with the ads before requesting the content via js but at this point I'd really start to question whether your regular users will stick around.