HTML 5 is heralded as the webs answer to the rise of the mobile app. I’ve talked a lot about how I do not see a conflict between HTML 5 web and hybrid apps and natively built mobile apps. Both have a role to play in the right circumstances. One of the benefits touted for HTML 5 is that it just works everywhere. In this article for boagworld.com I discuss this myth and the need for platform dependant optimisation. Just as it has always been in the world of the web.