This metric has been tested on the Wikipedia articles, to determine the level of trust one can have in its authors:
"We compute the reputation of Wikipedia authors according to how long their contributions last in the Wikipedia. Specifically, authors whose contributions are preserved, or built-upon, gain reputation; authors whose contributions are undone lose reputation.
We call this a content-driven reputation, since the reputation is computed automatically via text analysis. This contrasts with other reputation systems, such as those in use at [WWW] Ebay, where buyer and seller reputations are computed on the basis of user-provided ratings." (http://trust.cse.ucsc.edu/)
Technical paper at http://www.soe.ucsc.edu/~luca/papers/07/wikiwww2007.html