Been researching this type of system for about two years now. The feedback from business owners has not been very positive. Some do not want their inventory to be readily available to anyone (for whatever reason). Others do not see the value of anything outside of Facebook (the social network has become their own little internet). A couple talked about how expensive software is (they are right). One or two were open to the idea. But were not ready to be used as guinea pigs for research.
One common trait has been the lack of understanding of what online sales are, and what they might mean to them. There is a lot of space to innovate here, but it has to be done in a way that is less take a risk with me, and more this is totally safe and normal to do.