1. A method for generating digital event material and for event-based updating of user profiles UP of users U in a social network, said method comprising: a) providing an application server having support modules for performing the steps of: 1) maintaining a database of said user profiles UP; 2) mediating interactions involving said users U; b) compiling from self-reports and observed network behaviors of said users U a database of said user profiles UP having profile domains D; c) providing said digital event material and delivery parameters of an event E to at least one of said users U via a distribution server with a viral logic; d) enabling at least one group G of said users U to self-organize and to communicate a commitment to said event E through said viral logic; e) determining with a rules engine when said commitment reaches a predetermined threshold based on event responses ER of said users U; f) re-compiling said user profiles UP of said group G with an event-based updating module based on said event responses ER and identifying a profile change ΔP* in at least one of said profile domains D of said user profiles UP, whereby a new community is formed from said at least one group G based on said profile change ΔP*.