Originally Posted by murraypaul
Many smaller book stores use Adept DRM.
Major stores with their own associated ereaders do not. Amazon don't, Apple don't, B&N don't and Kobo only do when selling to non-Kobo devices, they use their own DRM for their own devices. Any (English-speaking) major player who has the option of using their own DRM rather than paying Adobe has taken than option.
Sony, B&N and Kobo (doesn't matter too much what they use internally) use Adobe DRM. Apple uses Fairplay. Amazon uses its own grown from Mobi DRM.
So most major stores use Adobe, not none as you say.