From it's old logo:
And now it's new logo:
Adsense new logo 2015
In my opinion, this logo represents or symbolizes stats. It might be statistics or performance report of a publisher's adsense ad units. That's the essence of adsense. The two-color new logo (yellow and blue) is similar to the color of the two characters of Google company logo which are letters O and G. (GOOGLE)
You can also see this new logo to the Adsense blog site (adsense.blogspot.com).
Adsense announced its new logo thru their Google Plus (https://plus.google.com/+AdSense/) page but no details have been said:
"AdSense has a new logo!We are proud to help people do more of what they love around the world."
Below is the video they published together with the announcement.
What can do you think of the new logo? Do you like this new logo?