One of the questions hanging in the air since Disney aquired Lucasfilm and Star Wars in 2012 and subsequently announced new films continuing the franchise's saga has been what all of that means for the Star Wars Expanded Universe. The Expanded Universe is a term used for all of the non-film stories made by many creators over the years, both to fill the void when there weren't any Star Wars films in production and to provide backstory and history to the universe and its many minor characters in ways that the films couldn't.
In the past, the expanded universe has been a secondary canon, with the primary canon being George Lucas' films and nothing else. Creators working in the expanded universe were expected to respect each other's contributions to the mythos, but when George Lucas wanted to make a new movie, he had to the right to ignore, override, or acknowledge the expanded universe as he saw fit (though he often chose to play nice. The name of the planet, Coruscant, and the facial scar Anakin aquires between episodes II and III both came from expanded universe stories that Lucas chose to go along with).
It seems that Disney plans to simplify the matter, according to the tweets of one Leland Chee. Chee is a member of the Lucasfilm Story Board, a group within Lucasfilm that has been charged with determining a singular, official Star Wars canon for the franchise to use going forward. Here's what Chee had to say:
Star Wars Canon is now determined by the Lucasfilm Story Group which @infinata and I are both a part of.
Story Group has a hand in all facets of Star Wars storytelling, including movies, TV, games, and publishing. More so than ever, the canon field will serve us internally simply for classification rather than setting hierarchy.
This is interesting news to hear coming out of Lucasfilm. Some fans feared that Disney would jettison the expanded universe mythos entirely to give future filmmakers the freedom to go where they pleased with their films, but it seems that Disney plans on keeping at least some of the expanded universe intact, though maybe simplified.
It will be most interesting to see what they decide to do with stories that take place after the original trilogy, during the same era the new films will take place in, including fan favorite stories such as The Thrawn Trilogy and Dark Empire.
Star Wars: Episode VII is scheduled for theatrical release December 18, 2015.