Influencers on the Web

This New York Times article discusses the patterns of social media networks.  The author states that research has confirmed that 80 -90% of content is generated from only 10% of the users.  These are the type of people who some think ruin these sites, but they are also the target of many marketers.  These influencers have a way of making their voice heard, and dictating the buying patterens of others. What do you think about these influencers? And should this type of pattern scare away marketers from the false presence of users, or direct them towards the smaller market of influencers?