The failure of the LA Times' wikitorial experiment brings to light one of the important factors for the success of commons-based publishing: the cost of policing it. Perhaps the best analysis of commons-based problems is Elinor Olstrom's book Governing the Commons. In it, she emphasizes through many analyses the importance of enforcing rules to the success of a collective endeavor.
As we look at the costs of blogs and wikis, in particular, we must build into that some measure of what it is going to cost to make sure that spam, pornography and other unwanted content is kept out. Today, there are technical tools to help you, but none of them are truly foolproof. You will need a person, or team of people, to keep an eye on things. By building the cost of this into the budget for the entire endeavor, you will rapidly come to a decision as to whether it is feasible or not.
The hitch in this is that we are still trying to figure out what the real costs are. There are no solid benchmarks yet that companies can use. Hopefully, we'll see more case studies and numbers so that we can make better decisions.
One other factor: Building and communicating the rules of proper behavior up front, then rewarding those who comply while punishing those who don't. We communicators need to study and understand human behavior in online communities so we can better prepare. More good reads? Virtual Community and Smart Mobs, both by Howard Rheingold.
Are you doing a cost-benefit analysis for your online publishing endeavors? If so, I'd love to hear from you.