Originally posted by Ed Greenwood:
Hi, Petter. Back in 1986, when TSR bought the Realms, they'd been aware of it since my articles in "The Dragon" (as it was then known) had started in 1979, and I'd been writing about it for 20 years or so. Having seen settings just "fall into limbo" when publishers went under or changed direction, I got some things put into my agreements with TSR over the years, and one of them was that everything I'd already written about the Realms, and would write or say, in interviews or at conventions, in the future, would be "official" or "canon" until something later published by TSR superceded it; WotC inherited this arrangement when they acquired TSR, and it still stands.
Anyone is free to have their own personal interpretation of what's canon FOR THEM, but that's the legal one, regarding canon FOR EVERYONE. Which they're stuck with, because they wouldn't know about the Realms AT ALL (unless they were in my local gaming group, or the readers of the long-running Campaign Hack zine, or readers of the Realms fiction published before TSR or D&D existed) except by virtue of that agreement.
The entire point of this, and the reversion clause, is that if the Realms ever vanished as a published imprint, I could continue to use it and publish new lore about it.
Hope that clarifies...