So I've been launching most of my sites recently in responsive design (where the layout shifts depending on the device / viewport) but I'm running into issues with regards to advertising.
I've pretty much come to the conclusion that, at this time, there's no good way to serve up AdSense on a responsive design site, and still maintain a good user experience, avoid click fraud (unnecessary clicks) and stay inside TOS.
Link units don't work at all - the smallest link unit is 468x15, I believe, and that won't work on an iPhone or otherwise 320x viewport. I mean, it displays, but scrolls off the screen. And if you have breadcrumbs, your link units can look mighty like breadcrumbs on a small screen.
468x60 ads are problematic as well. Google now "automatically" detects the device and serves a slightly differently formatted ad, but it still scrolls off the screen on my iPhone. Plus the ads are formatted kind of strangely - two of them, separated by a bar, with a condensed font.
300x250 ads in the sidebar work fine; the sidebar is usually served in a single column underneath your main content (on a WordPress site) - BUT if your user is scrolling down with his finger, it's difficult to avoid touching the ad, which could result in a lot of accidental clicks. Too many of them and you get frustrated users AND Google notices and sends you "the email."
Eventually they'll have to address this, but at the moment, the only solution I have is to keep using the mobile plugin (and not the responsive design), until Google catches up.
(The idea of using jquery has also been tossed about, but I'm not sure about the TOS there either)
Anyone else dealing with this yet? A third to half my (considerable) traffic is mobile now, and it's becoming more and more important.