I like the idea of customers being able to start their shopping experience on Facebook; e.g viewing selected inventory on Facebook - or any other site for that

I like the idea of customers being able to start their shopping experience on Facebook; e.g viewing selected inventory on Facebook - or any other site for that matter - potentially allowing them to add a product to their cart, and then drawing customers back to a main e-commerce site to continue and finalise purchase. The idea of having a total shopping experience hosted within the Facebook ecosystem worries me, because it places too much control in the hands of an organisation that's known to be capricious.