Castronova and Fairfield’s paper on “Dragon Kill Points: A Summary Whitepaper” 
Abstract: "This piece briefly describes the self-enforcing and non-pecuniary resource allocation system used by players in virtual worlds to allocate goods produced by a combination of player effort (the effort required to organize a group and overcome challenges) and the game itself (which "generates the good" the input here is the time of the design staff). For historical reasons, these systems are commonly called DKP Dragon Kill Points. The following is an attempt at a fun, not a thorough, discussion of the subject and some of the puzzles it raises."
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=958945#PaperDownload
Abstract: "This piece briefly describes the self-enforcing and non-pecuniary resource allocation system used by players in virtual worlds to allocate goods produced by a combination of player effort (the effort required to organize a group and overcome challenges) and the game itself (which "generates the good" the input here is the time of the design staff). For historical reasons, these systems are commonly called DKP Dragon Kill Points. The following is an attempt at a fun, not a thorough, discussion of the subject and some of the puzzles it raises."
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=958945#PaperDownload
