Google is testing adding a “Mobile-Friendly” tag onto the front of the description lines of Google AdWords ads.The example occurred for queries on Google Canada, and looks quite similar to the mobile friendly tags within organic search:
Of course the overall landing page experience plays a big role in quality score, and the mobile page effectiveness has been part of the scoring. This appears to only be a test at the moment, we are reaching out to Google for further comment.
A Google spokesperson confirmed that this is a test but does not have any impact on Quality Score.
This test would be big for those into mobile targeting as it does help an ad standout in the current iteration.
Source : Search Engine Land