While Shazam's mobile version is primarily used to identify specific songs playing while you're on the go, Shazam for Windows 8 is better used as a means of getting even more information on music. You can buy tracks, as well as watch music videos and concerts from YouTube. Users can learn lyrics or read album reviews and artist biographies with ease on Shazem as well.
There's also a social element to Shazam. You can share your music tages on Windows Live, Facebook, Twitter, and other social networks.
Shazam for Windows 8 is also nicely designed to make use of the touch screen. You can click a button to identify songs right from the interface, which is convenient. It won't always get a match for lesser known songs and artists though.
For mainstream song information, Shazam is a worthwhile app to add to your Windows 8 Modern UI.