WotC uses Silverlight for their online D&D 'Character Builder' -- it is effectively a core product along with the standard rule books. (PHB, DMB, MM) Tis some

WotC uses Silverlight for their online D&D 'Character Builder' -- it is effectively a core product along with the standard rule books. (PHB, DMB, MM) Tis somewhat niche, but D&D is king of that particular niche.