Just how smart are search engine bots?. Good Article
seomoz.org/blog/just-how-smart-are-search-robots?utm_source=bronto&utm_medium=email&utm_term=Just+How+Smart+Are+Search+Robots%3F&utm_content=Moz+Top+10+-+December+2011%2C+Issue+2&utm_campaign=Moz+Top+10+-+December+%232