Denser networks have shorter paths, so they transmit information more quickly. Networks broken up into subgroups diffuse information quickly within groups, but have trouble getting information moving between groups. According to Granovetter, weak ties are particularly important in diffusion. Studies show that most jobs are obtained through network connections, and that among those getting a job via connections, the vast majority get them through weak ties. The reason is that strong ties create dense little knots of people who share and reshare the same old information.
Novel information comes in from connections with people outside one's clique.
Hence, weak ties are especially important for network diffusion. The more ties, the more chances of hearing about something. Closeness is proportional to the average distance from the person to all others via the fastest possible routes. The smaller the number, the more central the person. Closeness is also important for predicting the speed with which different network structures can solve problems.