For most people, spam is a nuisance. Behind this nuisance, however, is a profitable business operation that continues to thrive despite the billions of dollars spent trying to disrupt it. This talk will cover the technical and economic foundations of spam and its evolution as a profit-seeking enterprise, including the emergence of affiliate programs. Using data collected across several research studies, Levchenko will explain the business of spam, from users who buy spam-advertised products to spammers making millions. The talk will describe prior work that identified payment processing as a key bottleneck in spam monetization as well as the results of applying this technique to stores selling spam-advertised goods, and its effect on spam operations. Levchenko will also cover the relationship between spam and other underground activities, including botnets and account compromise.