Matt Mullenweg once said they only serve ads on wordpress.com if the referrer comes from a search engine or similar. They didn't want to "punish" regular blog r

Matt Mullenweg once said they only serve ads on wordpress.com if the referrer comes from a search engine or similar. They didn't want to "punish" regular blog readers by throwing ads in their face. Nice concept, though I can't vouch for whether or not they actually do this...