The Wikipedia community relies on the No Original Research core policy to combat unsubstantiated claims from finding their way into articles:
Nutshell http://upload.wikimedia.org/wikipedia/commons/c/ce/Nutshell.png This page in a nutshell: Wikipedia does not publish original thought: all material in Wikipedia must be attributable to a reliable, published source. Articles may not contain any new analysis or synthesis of published material that serves to advance a position not clearly advanced by the sources.
The very purpose of this site as defined by the FAQ contains nearly exactly the same idea (my emphasis):
Skeptics - Stack Exchange is for skeptics, rationalists, free thinkers, or anyone who questions pseudoscience. Skeptics is about applying skepticism — it's for researching the evidence behind the claims you hear or read.
The voting system of Stack Exchange is largely meant to relax any need for specific policy regarding what constitutes a valid answer (and by and large it accomplishes this) — however, due to the nature of Skepticism, the community (and perhaps the FAQ) ought to promote the idea of no original research to encourage healthy voting.
Bad: (all seen in answers here)
- "...since I have personally experienced it numerous times"
- "Anecdotally, I've seen it..."
- "I heard that it was also caused by ..."
- "I'm not sure if this idea comes from some research"
- "There is a fairly comprehensive article on the topic at..."
- Even better, multiple sources
- One answer which contained no citations but did contain a thoughtful experiment, and therefore a net positive: http://skeptics.stackexchange.com/questions/1208/is-this-proof-of-geocentrism-scientifically-valid/1212#1212