I received a reply this morning to an email I sent Google regarding the changes to the 'Ads by Goooogle' text certain publishers have been noticing on their pages. Here is the contents of the email I received from a member of their AdSense team. I thought it would be useful to post it up here. So yes, this is just beta testing to determine whether or not the image affects your CTR. Nothing to worry about just yet!
Yep! We do keep on seeing the testings in AdSesne ADs formats. BTW, it is nice that you went one step ahread and talked to google itself
thanks matt. It's good to get the info from the source instead of all the speculations that can occur.