It seems strange the word 'dungeon' is used as often as it is for a roleplaying adventure site, given it's rarely actually a dungeon at all. But that's beyond the scope of this post.
This is a D36 list of reasons for a site not working out or even existing. I'm hoping jasons at the enjoyable The Dungeon Dozen hasn't already written a table on the same theme.
- Unbuilt: 1) conceptually unobtainable; 2) just a dream, hallucination or fantasy; 3) successfully foreseen and terminated at source; 4) all supplications rejected; 5) creator suffering self-doubt; 6) sketched on back of envelope, but then sent
- Unvisited: 1) wording of rumour alienates most or all adventurers; 2) local NPCs not consulted by creator and withholding recognition; 3) disguised too cunningly; 4) ahead of its time; 5) buried in sandbox; 6) DM has that strange glint in eye...
- Inaccessible: 1) non-existent pocket universe; 2) built out from within, entrance never added; 3) arcane means of entry lost or forgotten early on in development; 4) not at scale of landscape; 5) too few dimensions; 6) statted for wrong system
- Unbalanced: 1) unexpected evolution of one or more occupants; 2) emptied by surprisingly effective trap; 3) entirely filled by fast-spreading mould; 4) grew to encompass all of reality; 5) trapped in temporal loop; 6) cleared by playtesters
- Repurposed: 1) creator rethought alignment; 2) creation not having any of that; 3) revolution launched by occupants; 4) repossessed by backers and put to more profitable use; 5) domineering collaborator, aggressive editor and/or proofreader with ulterior motives; 6) exploited by malwayre infection from external netwyrk
- Destroyed: 1) mortar or equivalent lost in unanticipated interaction; 2) collapsed under weight of treasure; 3) consumed by magical chain reaction; 4) demolished by higher authority for breach of terms; 5) killed creator's grandfather; 6) victim of generational change, hoping for old school renaissance with little fresh thinking