I've only been on Shapeways a couple of months but I already have run into things like the Wall Thickness Lottery. I know that Shapeways contacts the buyer and cancels the order but it would be really nice if there was a way of the creator being able to contact the customer to tell them when the model has been fixed and such. Its very easy to lose an impulse purchase through not being able to tell people what's going on with your models. For that matter some form of limited shop blog would be awesome. Someplace you could post updates on what is being worked on or maybe polls for requests. It doesn't even have to be shapeways run, something like a webpage embedded in the store's face site that links to a Blog Spot blog or some such.