I've been trying out Google Music's All Access service ($7.99/month if you start the free trial before June 30th) as an alternative to Spotify. While I haven't decided which one I will continue using, there was one feature I needed before I could even consider Google Music: media key support.
Many keyboards have special keys that allow you to play, pause and skip tracks while listening to music. These keys usually work automatically with desktop applications that play music, but it's a different story with web browsers. Since Google Music doesn't have a desktop application, I needed another solution.
Check out the excellent Sway.fm Unified Music Media Keys extension for Google Chrome. This works on Macs and PCs1, and lets you control a variety of websites using your media keys. The list includes Google Music, Pandora, Rdio, Grooveshark, Last.fm, and more. Seriously, check it out.
For troubleshooting purposes (or if you're curious), I'm including some information about how the plugin seems to work on Windows. The plugin will intercept the keyboard presses
VK_MEDIA_PREV_TRACK. It does not intercept
WM_APPCOMMANDs. By default, keyboards should send the scan codes for the virtual keys properly, but enhancement software (like Microsoft's IntelliType / Mouse and Keyboard Center) can get intercept these presses and issue app commands instead. You will either need to disable this software or reconfigure it.2