This is described at http://meta.wikimedia.org/wiki/User:Agtfjott/Article_quality_and_user_credit...
The first work on such a system is an article at (From 12. mar 2006) http://no.wikipedia.org/wiki/Bruker:Agtfjott/Artikkelkvalitet_og_brukeretter...
This article is now deleted. Links to the article at meta are posted both here, at #wikipedia, #wikimedia and several other places so it can hardly be an unknown approach to anyone.
It is also discussed to set it up as a project together with Norwegian Computing Center http://en.wikipedia.org/wiki/Norwegian_Computing_Center
John E
Erik Moeller wrote:
The University of Santa Cruz/California has an interesting demo up that computes author trust based on whether users' edits are kept/improved or reverted. It then highlights passages of the text according to the computed reputation of the author who added them:
http://trust.cse.ucsc.edu/ http://enwiki-trust.cse.ucsc.edu/index.php/Special:Random
NB, this is still very experimental, but it seems promising.
Luca de Alfaro, who did most of this work, will also be presenting at
Wikimania.