Interesting article using the clunky term of 'social interest sites' to describe instantiations of the social form that Terry Anderson and I describe as the Set, noting rapid growth. There has been a lot of discussion of social networks but I think it is at least as important (and revealing different things) to talk about social sets. It is notable that much of the sharing on the Landing has relatively little to do with networks and a great deal to do with sets, and the same is true of a vast number of high profile sites including Twitter, Tumblr, Pinterest, YouTube, del.icio.us and Wikipedia. It is not that networks are unimportant - Twitter is just as strong on social networking, for instance, and sets are probably one of the most important means to discover and extend networks - but we have collectively paid too little attention to the set modes of interaction that are among the most common on the Internet