Are authors' blogs censored by their publishers?

Censorship always generates a lot of great discussion. Especially among my writer friends. I love that blogs are a great marketing tool for a lot of recent authors. But I wonder if any of that marketing is censored by publishers? Granted, a crazed fan might be deleted for stalking behavior and bad language. And maybe all the nasty reviews get the boot. If an author writes a blog about their book, at what point does the "deletion of objectionable information" leave the authors hand? Or is there any censorship at all?

What do you think?

Side Note: I've been reading about blogs and censorship on The Meaning of Blogger's Flag , which is a forum that discusses flagging blogs on Google's blogging tool: Blogger