Consumers use brand-related user-generated content (UGC), such as online consumer reviews, for their pre-purchase information seeking. However, previous research on consumer information seeking has scarcely explored how purchase situations and product type influence consumers’ use of brand-related UGC. The purpose of this dissertation is to shed light on this area of research. In the first part of the study, Vaughn’s (1980; 1986) Foote, Cone, and Belding (FCB) grid, a popular product classification theory in advertising and consumer research, was updated based on a set of online surveys (N=1,104) that measured three purchase dimensions [i.e., purchase decision involvement (PDI), think/feel purchase, online/offline purchase context]. Multiple research hypotheses relevant to how purchase type influences one’s brand-related UGC seeking were explored, based on another set of online surveys (N=391) in the second part of the study. A Cronbach’s alpha test revealed that the think/feel purchase dimension of the FCB grid measured two purchase constructs, rather than measuring a single construct. The grid model now consists of 118 up-to-date product examples and 35 categories, and has improved usability for research in other fields, because the study altered the theory’s dichotomous-looking dimensions into non-dichotomous variables. To examine the hypotheses, a linear mixed effect model was utilized for analysis, and the results indicated that the four dimensions (PDI, think purchase, feel purchase, online/offline purchase context) are all positively associated with one’s reliance on brand-related UGC. Furthermore, the study found several more associations between demographic factors and consumers’ reliance on brand-related UGC. Age, gender, marital status, number of children in a household, and employment status showed significant associations, whereas education, household income, and ethnicity did not. The dissertation has several implications. First, ad practitioners may use the updated product grid to define overall themes of advertising (e.g., informative vs. emotional theme). Second, marketers can use the study results to determine their budgets for online brand promotions. Finally, the study may also provide implications to scholars whose research explores pre-purchase information-seeking, influences of product type on decision-making, consumer involvement, emotional/rational purchase decisions, and brand-related UGC.