I believe that the general idea is that members should not post anything that they wouldn't want their boss or their mother to see on the screen.
So we would prefer not to see serious profanity.
About book uploads: it would be prudent to mention if the book is particularly controversial, so that members can make an informed choice about whether to download it.
We don't want to censor ideas, but we would prefer people to discuss them courteously. And we definitely don't want to see name-calling and other insults.