In a "Featured Homepage Discussion," [webmasterworld.com] Brett Tabke describes a Google experiment that could lead to the following scenario:

Imagine, just mousing over a result on a serp, and having that result open up further and further - showing you more-n-more information from that site.

This could be a game-changer for AdSense publishers:

1) Sites with useful content and effective page design would be at an advantage in the SERPs.

2) Sites that were designed as AdSense platforms (such as those that display three ad units above the foldt) would see their Google search referrals and AdSense revenues shrivel.

If you haven't read the thread, now is a good time to do so:

[webmasterworld.com...]