As is obvious from the post, Fred meant a list services that are used to publish lists for others to consume. Lists like the MacRumours&#x27; Buyer&#x27;s code mentioned in the top comment. <a href="http:&#x2F;&#x2F;buyersguide.macrumors.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;buyersguide.macrumors.com&#x2F;</a><p>There&#x27;s an obvious network effect: producers and consumers, more of each makes the service better, if producers get something as a return, even if it is just silly internet karma points.