Building Web Reputation Systems- P15

Building Web Reputation Systems- P15:Today’s Web is the product of over a billion hands and minds. Around the clock andaround the globe, people are pumping out contributions small and large: full-lengthfeatures on Vimeo, video shorts on YouTube, comments on Blogger, discussions onYahoo! Groups, and tagged-and-titled Del.icio.us bookmarks. User-generated contentand robust crowd participation have become the hallmarks of Web 2.0.
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Building Web Reputation Systems- P15Content ReputationContent reputation scores may be simple or complex. The simpler the score is—thatis, the more it directly reflects the opinions or values of users—the more ways you canconsider using and presenting it. You can use them for filters, sorting, ranking, and inmany kinds of corporate and personalization applications. On most sites, contentreputation does the heavy lifting of helping you to find the best and worst items forappropriate attention. When displaying content reputation, avoid putting too many different scores of different types on a page. For example, on the Yahoo! TV episode page, a user can give an overall star rating to a TV program and a thumb vote on an individual episode of the program. Examination of the data showed that many visitors to the page clicked the thumb icons when they meant to rate the entire show, not just an episode.KarmaContent reputation is about things—typically inanimate objects without emotions orthe ability to directly respond in any way to its reputation.But karma represents the reputation of users, and users are people. They are alive, theyhave feelings, and they are the engine that powers your site. Karma is significantly morepersonal and therefore sensitive and meaningful. If a manufacturer gets a single badproduct review on a website, it probably won’t even notice. But if a user gets a badrating from a friend—or feels slighted or alienated by the way your karma systemworks—she might abandon an identity that has become valuable to your business.Worse yet, she might abandon your site altogether and take her content with her.(Worst of all, she might take others with her.)Take extreme care in creating a karma system. User reputation on the Web has under-gone many experiments, and the primary lesson from that research is that karma shouldbe a complex reputation and it should be displayed rarely.Karma is complex, built of indirect inputsSometimes making things as simple and explicit as possible is the wrong choice forreputation: • Rating a user directly should be avoided. Typical implementations require a user to click only once to rate another user and are therefore prone to abuse. When direct evaluation karma models are combined with the common practice of stream- lining user registration processes (on many sites opening a new account is an easier operation than changing the password on an existing account), they get out of hand quickly. See the example of Orkut in “Numbered levels” on page 186.176 | Chapter 7: Displaying Reputation • Asking people to evaluate others directly is socially awkward. Don’t put users in the position of lying about their friends. • Using multiple inputs presents a broader picture of the target user’s value. • Economics research into “revealed preference,” or what people actually do, as op- posed to what they say, indicates that actions provide a more accurate picture of value than elicited ratings.Karma calculations are often opaqueKarma calculations may be opaque because the score is valuable as status, has revenuepotential, and/or unlocks privileged application features.Display karma sparinglyThere are several important things to consider when displaying karma to the public: • Publicly displayed karma should be rare because, as with content reputation, users are easily confused by the display of many reputations on the same page or within the same context. • Publicly displayed karma should be rare because it can create the wrong incentives for your community. Avoid sorting users by karma. See “Leaderboards Considered Harmful” on page 194. • If you do display it publicly, make karma visually distinct from any nearby content reputation. Yahoo!’s EU message board displays the karma of a post’s author as a colored medallion, with the message rated with stars. But consider this: Slashdot’s message board doesn’t display the karma of post authors to anyone. Even the dis- play of a user’s own karma is vague: “positive,” “good,” or “excellent.” After orig- inally displaying karma publicly as a number, over time Slashdot has shifted to an increasingly opaque display. • Publicly displayed karma should be rare because it isn’t expected. When Yahoo! Shopping added Top Reviewer karma to encourage review creation, it displayed a Top Reviewer badge with each review and rushed it out for the Christmas 2006 season. After the New Year had passed, user testing revealed that most users didn’t even notice the badges. When they did notice them, many thought they meant either that the item was top rated or that the user was a paid shill for the product manufacturer or Yahoo!.Karma caveatsThough karma should be complex, it should still be limited to as narrow a co ...