It used to be that when a movie was finished, it was... well, finished. Done. Complete. You sent copies out to theaters and/or TV stations, collected the box-office receipts and/or Nielsen ratings, stuck the negative in a vault and moved on to your next masterpiece.
What a difference a little innovation like digital technology can make. "Films," which used to exist only as pieces of celluloid that had to be physically cut, spliced and otherwise fooled around with in a process requiring tremendous amounts of money and skilled labor, are much more fluid, loosely defined things now that ever-more-powerful computers have transformed how they are shot, edited, polished and delivered to consumers. The Wizard of Oz had a tangible existence as a set of film reels occupying a few metal cans, but Shrek is ultimately nothing more than a bunch of bytes of information on a hard drive, infinitely malleable and reproducible. Anybody with an iMac and some time on her hands can be a Phantom Editor, though of course there will always be more to the art of on-screen storytelling than deleting Jar Jar.