A short while ago, Amazon began selling a book on Pedophilia; not just about pedophilia, but about how to be a pedophile. This, understandably, caused some uproar. But when Amazon removed the book from their virtual shelves, some people cried that it was a violation of free speech. An article in the Vancouver Sun had a few things to say on this situation: "there's a distinction between banning a book and asking a seller to take it off the shelf. A boycott is a market mechanism between sellers and customers. It isn't a form of coercion."
This article argues that the removal of the book is not a form of banning, since it is not trying to get rid of the book from ever existing, but simply a marketing strategy that conforms to the desires of consumers. I have no reason to counter this argument. Personally, I wouldn't want that book on any bookstore shelves at all, but that is not to say that I don't think the author had a right to write the book and get it published. There are differences there.