The Google Ads policy on Expandable Ads will change around mid-September 2011. The policy is changing to allow ads to expand on mouseovers that last more than 2 seconds. This will be a global change. We made this decision to keep up with industry standards, as well as to accomodate advertisers' needs. After the new policy goes into effect, the relevant policy pages will be updated to reflect this change.
(Posted on August 30, 2011)