What functionality is missing? What is unsatisfying with the current situation?

  Having come to World Anvil from Realm Works, the thing I find most lacking in World Anvil is the ability to use content from another realm in my own realm. At this point, most of what I use World Anvil for is for the World Membership to the Lost Lands world from Frog God Games. But having to integrate any of that into a custom world is, frankly, to much work. So, despite having a Grandmaster-level membership, I've barely used World Anvil at all.    World Anvil is great to build things from scratch, but if I want to subscribe to a pre-created world or adventures, such as the Lost Lands, World Anvil is severely lacking.  I either have to recreate everything and cut in paste from content already in World Anvil or make sure all my players have world memberships to the other world and manually link. The World Membership functionality is just not designed for convenient use.    I've renewed my Grandmaster Subscription for another year, mostly because I still find my Lost Lands world membership very useful, but I'll likely downgrade my membership to the lowest level to give me continued access to my world memberships, or just go back to working with PDFs.   

How does this feature request address the current situation?

  If there were a way for me to easily reveal content from a World Membership to my players and annotate it with my campaign-specific notes, I would be locked into World Anvil and would happily continue to pay Grandmaster or higher membership. Nothing would lock me more into World Anvil than this. I realize this is a big development challenge, I saw how difficult it was for the Realm Works team, but other products like VTTs provide ways to purchase content that can be shared with players. I would think that a well implemented mechanism for revealing and annotating world-membership content would increase the user base. Most TTRPG players and game masters are not building worlds from scratch.   

What are other uses for this feature request?

  It would make WorldAnvil a viable market for their content. It has proven a good business model for VTT products, I don't see why it would not be similarly lucrative for campaign-management systems.