We introduce a simple two-stage game of endogenous network formation and information sharing for reasoning about the optimal design of social networks like Facebook or Google+. We distinguish between unilateral and bilateral connections and between targeted and collective information sharing....

I quantify spillovers of attention in a network of content pages, which is challenging, because such networks form endogenously. I exploit exogenous variation in the article network of German Wikipedia to circumvent this problem. Wikipedia prominently advertises one featured article on its main...