Much coverage of the Internet focuses on undesirable, sometimes intrusive, communication, often referred to as “spam.” Spam has been decried as antisocial, wasteful, and/or fraudulent, with individuals, organizations, and media reports widely advocating regulation or outright banning of the practice, yet no uniform definition exists. Participants in the electronic communication and commerce process generally operate on an “I know it when I see it” basis that is shaped by their personal experience and expectations. This chapter begins with a brief history of this new medium, then defines spam within a typology of undesirable Internet communications. Conflicting definitions of spam are examined in light of their implications for suggested remedies. The paper concludes with recommendations on controlling spam for individuals, managers, and policy makers.