Product selection in online marketplaces

A marketplace such as Amazon hosts many products by third party sellers and acts a first or private label retailer. Assuming an advantage of in logistics marketing, we investigate whether entry is excessive from the point view consumers. With competitive sellers, may be either overprovided underprovided, but incentives consumers are correctly aligned for family power surplus functions (generating instance linear, isoelastic, loglinear demands). Competition customers with other retailers reduces commissions prices preserving efficiency result. Market increases (reduces) to retail (first party) products, generates bias toward underprovision entry. We extend analysis delivery fulfillment marketplace, product differentiation price competition on platform, dynamic enter launch copycat products.