1. A method for disseminating messages in a communication system, comprising: at a server having one or more processors and memory storing instructions for execution by the one or more processors: for a respective message in a plurality of messages: identifying users in a plurality of users for whom there is a match between one or more words in the respective message and a focus specification index generated for the plurality of users; sending to the identified users the respective message; and receiving from at least a subset of the identified users feedback data regarding a respective author of the respective message; evaluating the feedback data for identifying one or more popular messages associated with the respective author; and in accordance with the identifying of one or more popular messages, sending at least a portion of the one or more popular messages to a second plurality of users.