From P2P and Grids to Services on the Web (2nd ed.)

Over the past several years, Internet users have changed in their usage p- terns from predominately client/server-based Web server interactions to also involving the use of more decentralized applications, where they contribute more equally in the role of the application as a whole, and further to d- tributed communities based around the Web. Distributed systems take many forms, appear in many areas and range from truly decentralized systems, like Gnutella, Skype and Jxta, centrally indexed brok