I sell my info product and it had been successful until one of the Google's updates and my rankings went down a lot. Now the best SEO strategy seems to write good content articles rather than getting more and more of backlinks. Anyway, to do that, I have to write many high quality articles on the topic, and it is kind of impossible to do so without revealing the content of the paid product. I wondered how other people(info product sellers) were dealing with this part and did some Googling, then I found this article.
Here, the author says that the primary reason people buy is not the content itself, but more about experience, access, convenience etc. so it is OK to give away most of the information on your blog, and he says he generally goes with the 80:20 ratio.
He says that people think that "if the free information is this good, the paid product must be really good." and end up buying the product.
While I understand what he says, I'm not convinced if the customer is 100% happy if she/he noticed that information was available on the blog etc. They may be disappointed because they think there is nothing new.
So, my question for you guys is
(1)How much information do you give away for free?
(2)If you give away a lot for free, have you ever gotten complaint from a customer of the paid product saying they couldn't find anything new in the product?