Hatsune Miku is really quite interesting from a /cyb/ perspective desu. In a sense, she is a manufactured product, but the corporate producers did not define her identity: the fans did. It was they who wrote the songs, they who made the MADs, they who came up with the personality of the characters. It's like the Touhou secondary fandom – except the line between secondary and primary is dissolved entirely, because there is no centralized source material.
Sure, the entire community is based on proprietary software, but the content that community produces (which is the actual centerpiece of that community) treats that content in a very non-corporate way.