Anyone see this? May be old news... but new to me lol http://www.jensense.com/archives/2006/01/google_adsense_8.html
IMO, not worth implementing any of those. They just annoy your visitors. For instance, I hate how IGN's site has interstitial ads. The expanding ads could be promising, but then again I'd imagine all of these things not resulting in productive clicks.
Really depends upon your type of site I think. For my site, I agree, visitors would not be as receptive.