...but this discussion has to happen somewhere. If not in scourgicus' thread, where I originally posted my thoughts on the matter where it was uncalled for, then here. Excised of my typical inflammatory viciousness, this is what I said:
One can put boxes around whatever particular lore one wants, defined by whatever parameters one likes, but the truth of the matter is that in The Elder Scrolls, there really isn't an impenetrable wall between in-game lore that is exclusively true and out-of-game lore that can never be true and thus can never be considered for discussion.
This isn't even about ideology. It's about the factual record.
http://www.imperial-library.info/content/nu-mantia-intercept, an out-of-game lore document, was the direct foundation for the first lore book in Skyrim, the http://www.imperial-library.info/content/book-dragonborn. The ideas in the latter would literally not exist without the former.
http://www.imperial-library.info/content/many-headed-talos, an out-of-game lore document, was quoted verbatim in http://elderscrolls.wikia.com/wiki/Heimskr. Can't get any clearer than that.
http://www.imperial-library.info/content/five-hundred-mighty-companions-or-thereabouts-ysgramor-returned, an out-of-game lore document, was the direct basis for the Companions faction in Whiterun; the concept itself was established here.
http://www.imperial-library.info/content/magne-ge-pantheon, an out-of-game lore document, was the clear inspiration for the http://www.imperial-library.info/content/exegesis-merid-nunda in Elder Scrolls Online; the former portrays an extremely odd color-based Aetherial society and places Meridia in its number, while the latter references known Magna-Ge and places Meridia in their number.
http://www.imperial-library.info/content/vehks-teaching, an out-of-game lore document, was taken from liberally in the same Exegesis of Merid-Nunda I mentioned above. The description of Mnemoli (or Mnemo-Li), which prior to these was oblique to nonexistent in in-game lore, are virtually the same.
http://www.imperial-library.info/content/seven-fights-aldudagga, an out-of-game lore document, has two references to its credit - one in the painted cows and swirly aesthetic of Skyrim's giants (Kurt Kuhlmann can attest to the heritage of that), and a mention about the genealogy of giants in the official Emperor's Guide that came with special editions of Elder Scrolls Online, which, again, originated in the Seven Fights of the Aldudagga. I would link this reference, but it hasn't yet been uploaded to TIL.
You don't have to accept everything MK writes. I'll be the first to admit it's often quite up its own ass. I am not saying all of this because I am a slavish acolyte of the Elk. Anything but; I've sparred with MK quite publicly before. But to willfully ignore half a dozen examples of out-of-game work influencing later games and persist in labeling them "fanfiction" is absurd.
I will leave with a Kurt Kuhlmann quote:
"We all try not to take it to heart that only MK can save Skyrim from the trash heap - but I can say that even without directly writing any books, I'd say there's more of his influence on Skyrim than Oblivion. Probably a lot more - if you look at the chapter from the PGE on Skyrim, (pretty sure that was one of his - I can't remember any more who wrote which one, it's Bilbo and Strider all over again), and that chapter is the foundation for the whole setting. And if you look really hard, you might even find a painted cow. (No comment on flying whales.)"
Again, I'm not trying to insult anyone or incite a flame-war. This is an important discussion that needs to had frankly, with all due respect and politeness, for the sake of this forum.