When searching for a site, pages that primarily use Flash are clearly marked by Google with a warning that the site may not work on a particular device.
A common annoyance for web users is when websites require browser technologies that are not supported by their device. When users access such pages, they may see nothing but a blank space or miss out a large portion of the page's contents.Google goes on to recommend that websites use the universally supported HTML5 and provides both Web Fundamentals and a Web Starter Kit for website developers.
Starting today, we will indicate to searchers when our algorithms detect pages that may not work on their devices.
Apple received a good bit of criticism when the iPhone was first released for not supporting Flash as it was used often back then, but interest in Flash has since been dying out in favor of mobile-friendly solutions.