8. A computer-implemented data processing method of providing one or more activities to subsequent viewers of a piece of multimedia in a time-shifted manner according to an activity map, comprising: identifying, by one or more activity management servers, a plurality of segments that make up a piece of multimedia; receiving, by the one or more activity management servers, a plurality of activities from one or more users prior to a first time, each particular activity of the plurality of activities being associated with a respective particular segment of the plurality of segments; generating, by the one or more activity management servers, an activity map for the piece of multimedia based at least in part on the plurality of segments, the activity map indicating: the association between each particular activity of the plurality of activities and the respective particular segment of the plurality of segments; and one or more associations between one or more particular activities of the plurality of activities and one or more other activities of the plurality of activities; receiving, by the one or more activity management servers, from a client device, a first request to display one or more activities associated with the piece of multimedia; in response to the first request, generating a graphical display of the one or more activities associated with the piece multimedia based at least in part on the activity map, the graphical display comprising a word cloud generated based at least in part on a graphic density of one or more particular words that appear in the one or more activities; and causing the client device to display the graphical display.
8. A computer-implemented data processing method of providing one or more activities to subsequent viewers of a piece of multimedia in a time-shifted manner according to an activity map, comprising: identifying, by one or more activity management servers, a plurality of segments that make up a piece of multimedia; receiving, by the one or more activity management servers, a plurality of activities from one or more users prior to a first time, each particular activity of the plurality of activities being associated with a respective particular segment of the plurality of segments; generating, by the one or more activity management servers, an activity map for the piece of multimedia based at least in part on the plurality of segments, the activity map indicating: the association between each particular activity of the plurality of activities and the respective particular segment of the plurality of segments; and one or more associations between one or more particular activities of the plurality of activities and one or more other activities of the plurality of activities; receiving, by the one or more activity management servers, from a client device, a first request to display one or more activities associated with the piece of multimedia; in response to the first request, generating a graphical display of the one or more activities associated with the piece multimedia based at least in part on the activity map, the graphical display comprising a word cloud generated based at least in part on a graphic density of one or more particular words that appear in the one or more activities; and causing the client device to display the graphical display. 9. The computer-implemented data processing method of claim 8 , the method further comprising: receiving, by the one or more activity management servers, one or more additional activities, each particular one of the one or more additional activities being associated with a respective particular segment of the plurality of segments; and as the system receives each particular one of the one or more additional activities, substantially continuously updating, by the one or more activity management servers, the activity map to indicate: the association between each particular one of the one or more additional activities and the respective particular segment; and one or more associations between the one or more additional activities and the plurality of activities.