The study presented in this chapter aims at providing the foundation for future research examining the potential negative results of open ads. In past decades there has been a shift toward ads with less guidance toward a specific interpretation. Different terms have been used to denote these ads-for instance, complex image ads, implicit ads, ambiguous ads, and undercoded ads. Open ads have the common characteristic that consumers are not manifestly directed toward a certain interpretation. We formulate five antecedents that render an ad more open: presence of a prominent visual, presence of rhetorical figures, absence of the product, absence of verbal anchoring, and a low level of brand anchoring. We distinguish four categories of open ads: riddle ads, story ads, issue ads, and aesthetic ads. Although the literature generally stresses positive outcomes of openness on consumer reactions, five experiments show preliminary support for the arguments stressing a possible dark side of openness for consumer response. We have found negative effects of openness on interpretation, attitude toward the ad and the brand, and null-effects on attention and recall.