Google has started adding "Ads by Google" to more of its ads around the web. The reasoning for this is that a lot more advertisers are using Google's rich media ad formats these days, and the fact that they come from Google may not seem so obvious all the time.
"You'll soon notice a small 'i' (for 'information') icon overlay in the bottom right-hand corner of these ads, which will expand when the user hovers over it," explains Dan Friedman from Google's Inside AdWords crew. "This was specially designed for rich media ads. This new message will appear on your AdWords rich media ads, and will show up on standard AdSense ad units."
It will look something like this:
Google also recently started adding YouTube promoted videos into the AdWords/AdSense mix. In addition, they have introduced a new way for local businesses to advertise, and given advertisers more tracking options.