This document discusses the differences between cross-sells and upsells in ecommerce. It states that an upsell is getting a customer to spend more money on a more expensive version of the same product, while a cross-sell is getting a customer to purchase an additional product from a different category. It provides examples of upsells and cross-sells for an iPod purchase. The document also notes there should be a third category of "alternative products" that are more navigational than aimed at increasing purchase amounts.