For social networking companies, I believe that it means targeting influencers to take advantage of their networks' coverage is much less powerful than first thought. An advertiser won't expect to be able to steer dollars towards just a few of the truly deeply connected influencers and gain outsized rewards; instead, they'll have to target lots of influencers, reducing the ROI of the project.
Even more than that, the structure of these networks imply that targeting influencers may be ineffective. There's an interview [0] with Duncan Watts discussing this.
