I think we need a special; marketplace entity, that allow you to buy / display marketplace item. Also think this Specialy marketplace entity can only be placed manual inworld, this makes it think abuse it a bit harder. Other thing would be top use the marketplace website only for searching with a link to the inworld shop. maby the item only appears in the marketplace site after you have placed marketplace entity in the inworld shop and configured that.
Really would be so much better if people can shop inworld again, that made the virtual world much more immersive and i can say, im missing that.
Just some thing that where in my mind.