The Scrivener's Error blog has a piece on the rating of films (PG and so forth) which is worth a look if you are interested in the question of censorship. It is an old question -- why are we so terrified of sex, and yet will tolerate high levels of graphic violence in our movies? Yet it remains one of concern to parents.
And while you're peeking at Scrivener's Error, you might wish to go back to 4 August 2004 and read what he has to say about the 'boosterism of self-publishing' -- i.e. that list of famous writers who self-published at least some of their books. This list crops up, in one plagiarised form or another, on every web site which wants to persuade you to self-publish your book, using, of course, the facilities provided, for a fee, by the company which set up the web site. As C.E. Petit points out, the list is, to put it politely, misleading.