Google Adsense ads is testing simplified “Ads by Google” text, which blends better and makes Google Adsense ads look less like ads.
Here is what the Adsense ads looked like on most sites sometime back
And this is what Adsense ads are looking now on our site and many other popular sites.
You will notice the “Ads by Google” image has changed into text (of the same size as the url) in plain unbolded black and is hardly noticeable. It blends better and definitely make the ads look less like ads and will get a higher CTR.
Of course Google has experimented earlier by removing “Ads by Google” altogether, but I guess that hurt their branding. Are you seeing such ads on your site?