Western Digital Learns Art

Then, it was only green. Today, Western Digital (WD) decided that they require black and blue as well. Black denotes maximum performance and blue appears to be typical ones ...

Blue
Desktop - Performance and reliability for everyday computing.
Mobile - Big capacity for portable computing.

Desktop Drives now come in the 3 different flavors (i.e. black, blue and green); Mobile Drives have 2 to choose from, black and blue.
These colors will likely give WD an edge over their competitors as consumers can easily relate to their products more easily.
p.s. Technically, black isn't a color ... oh well.