Whereas in the past, the whole Adsense block units including the white spaces are clickable areas, Adsense has changed it to make only the ad title and URL as clickable. This according to the Adsense Blog post was implemented to reduce the incidents of invalid and accidental clicks on those ads and to encourage site visitors to stay on the site, interact with the site content and if they deemed it necessary, click on the ads.
The post further explained that the new clickable format aligns with the text ad formats that is being implemented on Google.com. The new format would also benefit Google advertisers by making them pay for ad clicks that were intentional and would contribute to the success of their ad campaigns.
Just before this post was made in the Inside Adsense Blog, it has already elicited various reactions from both bloggers and advertisers. For Adwords publishers, these will certainly increase advertisers campaign value and satisfaction. But for Adsense publishers, this may not be good news after all.