The usage of Peer to Peer Networks over the Internet has been growing by exponentially. Apartbfrom the hype surrounding P2P, it has remarkable ramifications on the way the Internet could be used. This is an area which is not explored as well as we would want to. This thesis examines the architectural differences in P2P networks and generic application domains where the principles of P2P are exploited. The usage of P2P in different business verticals and technology enablers that go along with it are presented. The focus is on several case studies each addressing a different use case. The common thread running through all of these use cases is the ability to resolve a business issue. Finally the focus is on how P2P networks might probably change the way the Internet behaves in the near future.