This paper analyzes different types of similarity judgments, including a distinction between quantitative and qualitative analogies. Then, a survey of the most frequent uses of both types of analogical judgments. The main goal of this paper is to highlight the variety of criteria that we should employ in determining the value of a similarity judgment, depending on its function. This is particularly relevant for the appraisal of analogical argumentation. In particular, we argue for the importance of distinguishing between analogical argumentation and classificatory argumentation.