How was yahoo supply chain modified from brick and mortar?

I am working with 3 web sites and need to know where to find the information. The 3 web sites are yahoo launch, Billboard and Napster. The question is describe the supply chain for the business area selected when in a ';brick and mortar'; environment. Explain how the supply chain was modified from ';brick and mortar'; by the web sites. Please help! I need to have it by 12 midnight. Thanks.