The Citizendium project is nothing if not intriguing. The drip-feed of information about it doesn't hurt in terms of provoking interest. Here's the latest two installments from Dr. Sanger: Why Make Room for Experts in Web 2.0? and The Role of Content Brokers in the Era of Free Content. I've not had time to digest them yet, but Larry writes well and interestingly, so they're likely to be worth reading.