From the moment words started being published censorship became an issue.  There will always be topics which offend all sorts of people.  This offense can lead to a desire to say a book (or other discussion of the topic) should be banned or censored.

PayPal, a company that offers a secure online payment method, last month issued an ultimatum to Smashwords a distributor and self-publishing company.  Smashwords helps authors publish their books.  In the erotic section of the books offered some books contain what PayPal doesn’t like – bestiality, rape, and incest.
On February 14, the head of Smashwords was informed by PayPal that their book list needed to be cleaned up or their account would be limited.  According to Smashwords website, they have over 100,000 titles from over 37,000 authors.  Coker, head of Smashwords, emailed authors who responded with outrage over this attempt at censorship.
PayPal asserts that the banks and credit card associations they deal with are conservative and they have to adhere to their demands or lose business.  Coker urged authors and publishers to voice their opinions to PayPal and the credit card companies.
PayPal recently did the same to Bookstrand which resulted in Bookstrand dropping most Indie authors.  Coker is working with PayPal, the authors and publishers, and censorship / free speech groups to resolve this issue.  Fourteen of these groups signed a letter to PayPal condemning their actions. 
In general most people would agree that these topics can be offensive.  However, almost all the Greek (and other Pantheons) myths involve rape, incest, and even bestiality.  Will those be banned?  Many famous and classic stories have been banned like Huckleberry Finn, Catcher in the Rye, and Catch 22.  Controversial issues spring up in many forms.  For instance, gun control and gun usage can fall under the controversial heading.  Does this mean we should prevent stories and books on hunting or murder mysteries from being published?  Last of the Mohicans couldn’t be allowed than because that features guns.
Censorship is a complex and difficult topic.  Obviously few think the erotic fiction being targeted is classic literature.  PayPal is attempting to provide a standard.  It’s meant to keep offensive writing away from the public.  The problem with this type of censorship is it becomes a slippery slope that will easily domino into a landslide of banning books – good and bad – that shouldn’t be banned.  Additionally whose standard will the companies adhere to?  The standards of a few groups shouldn’t prevent books and stories from being printed.  There are so many groups choosing one standard is likely to offend a number of others.  Where would we be without our myths and books like To Kill a Mocking Bird?  If authors don’t push the envelope than how does society look at itself to determine what needs to be changed?