$S$-measures are special fuzzy measures decomposable with respect to some fixed t-conorm $S$. We investigate the relationship of $S$-measures with some distinguished properties of fuzzy measures, such as subadditivity, submodularity, belief, etc. We show, for example, that each $S_P$-measure is a plausibility measure, and that each $S$-measure is submodular whenever $S$ is 1-Lipschitz.