As you've discovered, this is the Western Digital Drive Manager Service and may be a sub-program of Western Digital SmartWare. I believe it's used primarily by the WD My Book external hard drives. WD Support / Downloads / My Book / My Book Studio Edition II
If you don't now have any Western Digital drives (either internal or external) did you ever? Or did you ever let someone else attach an external WD drive to your machine? It should be perfectly safe to remove this service.