Let me preface my comments by stating that as a general rule, I'm opposed to censorship. *But*, if it is a forgone conclusion that there will be censorship on an issue, then I would prefer it to be (democratic) government regulated than corporation regulated.
As Chodon points out, corporate censorship can be changed with currency. However, the nature of corporations is such that it will only ever change in one direction - that of increasing the level of censorship.
To show this, lets take an example. Imagine that a new movie comes out where the main character constantly spits food on the people he eats with. About half of the population think it's justified because it's used to a comedic effect. Another 45% or so of the population are turned off by this, but they just don't watch the movie. The last 5% are really upset. "Movies are teaching our kids bad table manners!" they shout. They start a letter writing campaign to Blockbuster, Best Buy, Walmart, and other major retailers of movies and tell them to take the movies of the shelves.
Imagine that Walmart reacts by pulling the movie, and none of the other comapnies do. Well, if you want that particular movie, you will go to Best Buy or Blockbuster. But for all your other purchases, you'll still go to Walmart. On the other hand, Best Buy and Blockbuster will keep being pressured to remove the movie. They will have to deal with a large volume of mail, and with protestors outside the store, and with people calling up on radio shows and TV talk shows and saying "Blockbuster and Best Buy are ruining our youth!". After a while, they'll find it easier and cheaper to just remove the movie. Now, there is no longer any way to get the movie. So no-one gets the $10 you would pay for it. But the loss of $10 per movie is significantly less than the cost of dealing with a negative publicity campaign.
Now, of course there could be a counter-campaign raised by anti-censorship groups, but the problem is that they have to fight each censorship battle. The offended sides, however, will differ per issue. Sometimes it's religious people, sometimes its anti-religious people, sometimes it's anti-racism groups, sometimes it's anti-gay groups, and so forth. So there are a lot more of them, and they have fresh resources/energy each time. Some battles against censorship may be one, but the war is stacked in the favor of the complainers.
And corporations don't have to wait for complaints. A movie that might cause offense? Never stock it. If you have it on the shelf and remove it, people might hear about it, but if it was never there? You might never notice. Say Walmart silently decides that they will not stock movies that offend scientologists. Someone makes a documentary about Scientology, and Walmart never buys it Most people don't watch documentaries, so they don't care. They still shop at Walmart for other movies. Even most of the documentary crowd will not notice, as they will simply get a different documentary. They aren't aware that something is missing because they never heard about it.
Government censorship - in a democracy - has several advantages. One of them is that governments have a harder time to do things quietly. It's still possible to do so - stick a provision in some unrelated law or some other trick - but governments must publicize their laws, and people will notice. A corporation is under no legal obligation to report its censorship policies.
But most importantly, the equation is as follows:
- Government censorship can allow the majority to silent the minority. Therefore, it is bad.
- Corporate censorship allows majorities to silence minorities AND minorities to silence majorities. Therefore, it is far worse.
