Great post, Matt. Your call for a corrections notification system for readers is really on point. I've been trying to generate some interest in the idea of a "reverse trackback" that could also provide an automated way to notify blogs and other sites if an article they quoted has been corrected/updated. I wrote about it here:
http://www.regrettheerror.com/regret-articles/cor...

Also, you should check out the way Slate handles corrections; they have a very cool system that shows readers exactly where the mistake occurred in a given article.