Now a days most things don't remain in a single form once they become something 'big'. Movies get made out of every book that sells more then six copies and from there a horde of video games, comics and other assorted types of media can spawn. The question is, does the original content remain once it's been translated into a half dozen other forms?
Probably not, but it might.
One example is the Harry Potter books, written by J. K. Rowling. The book series has sold over 450 million copies as of June 2011 and is the best selling series in history. And it's been translated into 67 languages. The movies hold a similar record as the highest grossing film series in history. So, apparently they did something right
Reception wise, the books are loved by children around the world though not without their share of controversies. Opinions on the films however, vary. Due to a change in directors some fans believe they feel disjointed. The first two movies are very strict to the books though the later ones take on a more character driven and stylized form that some fans were not impressed with.
J. K. Rowling defended the movies saying, “It is simply impossible to incorporate every one of my story lines into a film that has to be kept under four hours long. Obviously films have restrictions – novels do not have constraints of time and budget; I can create dazzling effects relying on nothing but the interaction of my own and my readers' imaginations.”
Does the content remain the same in the later movies as it did in the books? The same characters fall in love, the same ones die and the plot remains more or less the same. But does it still feel like the Harry Potter books?
I don't think so.
Numbers and quote stole shamelessly from Harry Potter (Wikipedia) and Harry Potter Films (Wikipedia) like a lame ass.