How does information propagate in Twitter's network?

Twitter can be represented as a directed social network where nodes are the users of the service and edges represent "following" relationships. In NETS 312, we provide tools to study the propagation of information over the Twitter social network. For example, we consider the set of users (i.e., nodes in the network) who mention a particular tag in some chronological order, their distribution over the network, and the presence/absence of edges between them.