I present a model to assess the impact of demand-side factors on the concentration of sales within large product assortments. Consumers face a search problem within an assortment of horizontally differentiated products supplied by a monopolist. They may search for a product match by drawing...

"We study competitive interaction between two alternative models of digital content distribution over the Internet: peer-to-peer (p2p) file sharing and centralized client-server distribution. We present microfoundations for a stylized model of p2p file sharing where all peers are endowed with...