This mass email campaign from multi-million dollar newsletter publisher, Agora Inc., is promoting a free "controversial" book offer. The catch is, once you clickthrough...View More to the sales page, you realize the "free book" is yours only if you buy a yearly subscription to their newsletter. In the newsletter business, advertising & marketing "bonuses" instead of the actual newsletter is a successful go-to strategy & allows companies to constantly create new  angles that keep their marketing fresh & relevant. Each of the emails below has the same copy, but comes from a different Agora brand & are evenly spaced out time-wise from May into June. It gives you a glimpse into the power of having a network of different sites that can cross-sell related products.