This week during a panel discussion at the Open Mobile Summit in London, Andrey Doronichev, Google's executive in charge of YouTube, recently explained why the popular video sharing site has been slow in fully adopting HTML5.
There are several factors involved, the biggest of which is the cost of building apps using the new markup language.
"Building apps with HTML5 is its own skill, it's harder than [Apple's] iOS," he said. "The app has to work across Websites on different browsers, so browser fragmentation is an issue."
There's also a problem of distribution.