The major US-based search engine Google pressed the button to remove the popular service AdWords, Flash-based ads, which is one of the factors that played an important role in the spread of HTML5. A post on Google AdWords' Google+ page provided the following explanation:
"To improve the browsing experience across devices, Google Display Network and DoubleClick Digital Marketing are making a 100 percent transition to HTML5."
The transition to HTML5 will begin on June 30, 2016, when Google will block the loading of Flash ads on Adwords and DoubleClick. Advertisers will have 6 months to adapt their ads to HTML5.