 Analyzing Chwe’s models for collective action under the respect of weak versus strong links (cf. both Chwe 1999 and Chwe 2000) provides further insights about the interaction between communication networks and common knowledge. A strong link, roughly speaking, joins close friends, whereas a weak link joins acquaintances. Strong links tend to increase more slowly than weak ones, since people have common close friends more often than they share acquaintances. In terms of spreading information and connecting society, then, weak links do a better job than strong links, since they traverse society more quickly and have therefore larger reach. What role do strong and weak links play in collective action? In Chwe’s dynamic analysis, strong links fare better when thresholds are low, whereas weak links are better when players’ thresholds are higher. Intuitively, one sees that strong links tend to form small cliques right away (because of the symmetry intrinsic in them: my friends’ friends tend to be my friends as well); common knowledge arises quickly at the local level and, if thresholds are low, there is a better chance that a group tied by a strong link becomes a leading clique initiating revolt. If, on the other hand, thresholds are high, local common knowledge in small cliques is fruitless, and weak links, reaching further distances more quickly, speed up communication and building of the large cliques needed to sparkle collective action. Such considerations shed some light on the relation between social networks and common knowledge. While it is true that knowledge spreads faster in networks in which weak links predominate, higher-order knowledge (and, hence, common knowledge) tends to arise more slowly in this kind of networks. Networks with a larger number of strong links, on the other hand, facilitate the formation of common knowledge at the local level.