HTML5 kills off flash; HTML5 kills off Silverlight; HTML5 makes the dinner and does the ironing too. HTML5 is going to save the (tech) world. I've heard it all in the last year or two. Very rarely have I seen a balanced article or a writer that understands the concepts involved. Even worse are the (non technical) tech journalists who write an article on this subject purely to boost their own exposure.

This article attempts to provide a bit of history on the subject. It also attempts to pacify the situation and explain why it doesn't really matter.

This article focuses more on Silverlight than other technologies but the principles are the same for these too.