Every developer should understand Microsoft's Windows 8 - even the Mac and Linux developers. Love it or hate it, Windows 8 is entering the market. If you ignore it, you are simply ignoring what is likely to be the inevitable. As such, understanding the new concepts coming from Windows 8 as well as some of the jargon is important. Windows Store Apps will happen and will sit along side desktop applications. It is better to understand the impact on what you are doing, then to be left behind.