It has been a hot topic in Digital Point these days when more and more members are reporting the new 'Ads by Google' format. So far (I have personally experienced), there are two new formats for the 'Ads by Google' label. They are either a 'Google' logo or a big 'G' which replaces the original 'Google' text. See the screenshot below:
Just as we have holiday logos for our Google homepage and "Goooooooooogle" at the bottom of our search results, we thought "Ads by Goooooogle" would be a fun alternate version of "Ads by Google" for our AdSense ad units. They are both branding features we've tested, and we found that "Ads by Goooooogle" is often more memorable for users than "Ads by Google", so you may notice either label appearing beside your ads at any given time.And now Google might want to know if a big 'G' or a colourful 'Google' logo would be even more easy to remember.
|Update: There is a reply from Google AdSense Team from Search Engine Table:|
Thanks for your email - as you've mentioned, the change that you saw was part of ongoing testing to improve our ad formats. Such variations are a normal part of our testing process and generally run for short periods of time only. No permanent changes are planned at this time.