You may find this article of value, I did. http://www.insidesocialgames.com/2010/02/24/selling-digital-goods-stay-safe-and-reap-the-rewards/comment-page-1/#comment-13010 I just posted a comment about the use of CVNs (Card Verification Numbers). When they were first introduced, they confused people, but now some research I have seen shows that not asking for it can lead consumers to wonder if they are on a real site. Often, these new features are launched to much fanfare, go through a period of doubt, then at some point usually after the pundits have moved on, they actually matter.