JenSense reports AdSense Policies update time again!. There has been changes to the "Ad Placement", "Code Modification", "Incentives", Language", and "Prohibited clicks and impressions" sections. See JenSense for the details.
We have JenSense's detailed thread at WebmasterWorld, but if you do not like WebmasterWorld, you can go over to the DigitalPoint thread that is discussing this topic.
