As a follow up to my last post, a couple of folks decided to dig a little deeper on the recent research that showed wikipedia and the Encyclopedia Britannica have about the same error rate. As it turns out, most of the articles that were examined were much longer on wikipedia. So if you look at errors per bytes of text, the wikipedia is actually more accurate. From the article:
"Result: WP errors per 2KB: 1.3. Britannica: 3.6. WP average article size: 6.8KB. Britannica: 2.6KB"