The forum is provided as a free service. The ads are part of it and what you see are beta implementations being tested by Google - so expect to see it a lot more on other sites when it is officially rolled out.

Clicking the [X] to close the ad isn't going to take a whole lot of time, and the ads are usually capped to 2 maybe 3 implementations a day.

If its still that much of a bother to you, switch to the Desktop view as the new beta ads are only for mobile devices.