The latest fashion for Google now is to try and appear a little more professional in the "not greedy for clicks on ads" meaning of the word. It is the right way to go and it is a surprising move for a company that generates an astounding amount of its revenue from the clicks they draw from those interested.
What they did was to reduce greatly the area in which a click on an ad will direct you to the respective site, and by greatly I mean with about 80% or even more. Before this you could have clicked anywhere on the rectangle the ad was in and it would have been just swell. Many clicks by mistake were very likely to occur, but that suited Google fine and it's rather strange that this decision was taken now, before the Holiday shopping spree that would have really increased the number of clicks. They must have struck a nerve with someone and legal action was probably bound to be taken against them or I can't figure what else it could have been.
The decrease of the clickable area will most likely result in a decrease in AdSense revenues for almost every site using it, but on the other hand, it will most definitely trigger an increase in the value of the service for the advertisers.
This is the second time Google decides to implement the new and ethical change in play after previously decreasing the ad click margin for the ads in the search results page. The change isn't available everywhere at the moment, reports say that only the US users have seen this in action but it is strongly believed to be ready to hit Google subsidiaries all over the world by the Holidays.