From Amazon to Alibaba, marketplaces are helping drive e-commerce sellers to new heights even as department stores battle for relevance. As in any market shift, some will prosper and others fall by the wayside, and the new marketplace paradigm is no exception. While eBay is having a good year so far, plotting heavy investments in tech, launching shoppable content with Mashable and even creating an AR app to help sellers find the right-sized box — the marketplace landscape is still lorded over by Amazon, which alone accounted for 44% of online sales in the U.S. last year. Convenience is Amazon’s battlefield — and blood is being spilled by just about every retailer in the U.S. that tries to compete. As with every war, there will be victors and there will be casualties — it’s just a question of which side of the river you land on. Read more at Retail Dive.