The document discusses lead generation models on social media sites like SlideShare. It notes that social sites allow brands to support both branding and lead generation, where typically these are separate. The document outlines the continuum from cost per mille (CPM) to cost per lead (CPL) and discusses how lead generation works on older sites using content as bait. It also provides lessons learned from SlideShare's experience with lead generation, including shortening the loop between impressions and leads, optimizing user experience, and iterating quickly.