In a blog post on Mojang’s website, the developer highlighted some changes that they’ve made to their Guidelines that pretty much says that companies and politicians aren’t allow to promote themselves in the game. For example they’re not allowed to build a Minecraft mod or server that promotes an unplayable and unrelated product, like marketing a restaurant that’s made out of Minecraft blocks.
They also can’t use Minecraft to build a map or mod or a TV show or movie, or recreate a trailer using the game. However Mojang notes that this only applies to companies and individuals who might be using the game for commercial/promotional purposes (or who hired someone to do it for them).
They point out that fans and regular gamers are more than welcome to keep doing what they’re doing, so if you’re trying to recreate the Game of Thrones opening sequence in Minecraft, don’t worry, you can keep doing it as long as HBO did not hire you to do so.