I understand that we only have the content available from the SRD right now. When the rest of the content is released for those who have already bought the books, will we have to pay again for this content, or will we be able to unlock it with our ISBN number or something of the like?
While I would guess that you're right, I didn't see anything in that link to definitively state that there wouldn't be some way to get digital versions of products that we already own for free or at a discounted price. I may very well have missed it. Please point it out to me if I did.
In any case, I doubt that WotC would go that route based on their history with the few licensed digital services they've worked with (e.g. Fantasy Grounds, Roll20).
Indeed, as did for FantasyGround and Roll20, the will continue with the same model even here with DDB. There will be many options (one-time payment for the material and/or subscription for more features).
I understand that we only have the content available from the SRD right now. When the rest of the content is released for those who have already bought the books, will we have to pay again for this content, or will we be able to unlock it with our ISBN number or something of the like?
There will be the need of a one-time payment:
https://www.dndbeyond.com/forums/d-d-beyond-general/beta-testing-feedback/2271-ddb-staff-quotes-features-fixes-updates?comment=9
In any case, I doubt that WotC would go that route based on their history with the few licensed digital services they've worked with (e.g. Fantasy Grounds, Roll20).
Indeed, as did for FantasyGround and Roll20, the will continue with the same model even here with DDB. There will be many options (one-time payment for the material and/or subscription for more features).
http://www.dndbeyond.com/forums/d-d-beyond-general/general-discussion/825-mega-thread-user-thoughts-subscriptions-costs-and?comment=529