Google announced on Google+ yesterday a new form of display ad powered through Google+ named +Post Ads.
In short, +Post ads allow a brand to take their public Google+ content, photos, videos or Hangouts, and and turn that into a display ad on the Google Display Network.
Eran Arkin from Google said:
+Post ads will allow advertisers to start conversations right from the ad - consumers can reshare a video, leave a comment or a question for the brand, or even join a live Hangout. These conversations create a valuable community around a brand where people can talk with each other and with the brand itself.
Here is a video testimonial on how it all works:
For more details and pictures, see this page.
It is just a matter of time until we see ads on Google+, imo.
Forum discussion at Google+.