Friendly reminder that Foursquare still exists, from one of its early investors. :-)<p>But seriously, lists are useful because of their content. What a list does is condense information--an artifact of curation and maybe prioritization. So the value of the list correlates with its author.<p>Some lists are popular because they are curated by experts (newspaper restaurant reviews). Others are popular because they are curated by crowds, and thus express a collective social signal about what&#x27;s valuable (Reddit, HN).<p>So, I&#x27;d have to say that lists are a horizontal thing. Lists will succeed or fail based on their utility and relevance, which to me says that lists don&#x27;t really compete across verticals, except to the extent that everything competes for mindshare in general.