1. A method for detecting an event via social media content, the method comprising: determining, during a period of time in which a given event is not occurring, a background visual semantic concept signal level comprising a statistical distribution of multiple visual semantic concepts across multiple images from at least one social media source; obtaining multiple additional images from at the least one social media source; extracting at least one of the multiple visual semantic concepts from the multiple additional images; measuring the deviation of a signal level of the at least one visual semantic concept from the background visual semantic concept signal level to detect the occurrence of the given event in the multiple additional images, wherein a measured deviation of the signal level of the at least one visual semantic concept from the background semantic concept signal level that is above a predetermined threshold corresponds to the occurrence of the given event; and retrieving one or more images associated with one or more predetermined characteristics of the given event for presentation as a visual description of the detected occurrence of the given event; wherein at least one of the steps is carried out by a computer device.