One of the members of the Wikipedia technical team writes about the techniques Wikipedia uses to detect vandalism and fix mistakes.
Each contributor has a personal watchlist which will inform them of changes made to articles which they have registered an interest in. On average, each article is on the watchlist of two accounts. Relatively mainstream topics usually have more watchers, obscure trivia fewer or none (a hint to those who want to try circumventing this tool…). These watchlists are often checked several times a day, most within a week or so. Since these are usually topic experts, they are likely to detect any subtle changes which the RC patrol misses.
In a physical neighborhood, people watch out for their neigbhors houses and kids. A couple of weeks ago, a burglar taking electronics from my next-door neighbor’s home was foiled by a passerby, who nodded hello to a man walking down the street on the way out for breakfast tacos. On the way back, he saw the same man, leaving my neighbor’s home with a duffel-bag full of rectangular objects. He called the cops. My neighbor got her home electronics back.
Wikipedia’s alert system turns the 300,000+ article peer encyclopedia into a warren of virtual neighborhoods. People who have a common interest in a topic keep an eye out for problems and fix them as they happen. (The article also describes more hard-core techniques to block systematic vandalism)
Alex Halevais decided to test Wikipedia’s peer editing by inserting small errors into thirteen articles. The errors were caught and fixed within hours.