tailieunhanh - Building Web Reputation Systems- P4

Building Web Reputation Systems- P4:Today’s Web is the product of over a billion hands and minds. Around the clock and around the globe, people are pumping out contributions small and large: full-length features on Vimeo, video shorts on YouTube, comments on Blogger, discussions on Yahoo! Groups, and tagged-and-titled bookmarks. User-generated content and robust crowd participation have become the hallmarks of Web . | Molecules Constructing Reputation Models Using Messages and Processes Just as molecules are often made up of many different atoms in various combinations to produce materials with unique and valuable qualities what makes reputation models so powerful is that they aggregate reputation statements from many sources and often statements of different types. Instead of concerning ourselves with valence and Van der Waals forces in reputation models we bind the atomic units the reputation statements together with messages and processes. In the simple reputation model presented in Figure 2-3 messages are represented by arrows and flow in the direction indicated. The boxes are the processes and contain descriptions of the processes that interpret the activating message to update a reputation statement and or send one or more messages onto other processes. As in chemistry the entire process is simultaneous messages may come in at any time and multiple messages may take different paths through a complex reputation model at the same time. People often become confused about the limited scope of reputation and where to draw the lines between multiple reputations so we need a couple of definitions Reputation model A reputation model describes all of the reputation statements events and processes for a particular context. Usually a model focuses on a single type of reputable entity. Yahoo Local Travel Movies TV etc. are all examples of ratings-and-reviews reputation models. eBay s Seller Feedback model in which users ratings of transactions are reflected in sellers profiles is a karma reputation model. The example in Figure 2-3 is one of the simplest possible models and was inspired by the Digg it vote-to-promote reputation model see Chapter 6 made popular by . Reputation Context A reputation context is the relevant category for a specific reputation. By definition the reputation s reuse is limited to related contexts. A high ranking for a user of Yahoo Chess doesn t really