A digital signage system comprising: a communications interface connectable to at least one media store (210, 212) external to said digital signage system, each of the at least one media store storing one or more media assets deliverable to at least one viewing device; a media store for storing media assets; a user interface module configured to receive: i) access credentials for a custom channel producer to access the digital signage system, and ii) access credentials for the custom channel producer to access the at least one media store (210, 212) external to the digital signage system; an authentication module for verifying the access credentials of the custom channel producer to access the digital signage system; wherein the user interface module is further configured, responsive to said verification, to provide access for the custom channel producer to media assets in the media store of the digital signage system; wherein the communication's interface is configured to use the account access credentials for the verified custom channel producer to provide access to the at least one media store external to the digital signage system to determine what media assets are stored in the at least one media store external to the digital signage system; further wherein the user interface module is configured to: i) control a display of a terminal external to said digital signage system and associated with a custom channel producer to display media asset options, ii) detect selection by the custom channel producer of at least one media asset based on detecting selection of displayed media asset options corresponding to the plurality of media assets, wherein at least one of the selected media assets is stored in the at least one media store (210, 212), and iii) receive display parameters selected by the custom channel producer; the digital signage system further comprising: a custom channel controller coupled to the communications interface, the authentication module, and the user interface module, wherein the custom channel controller is configured to produce a custom channel comprising the selected media assets in dependence on said display parameters, and deliver said custom channel to the at least one viewing device. a communications interface connectable to at least one media store (210, 212) external to said digital signage system, each of the at least one media store storing one or more media assets deliverable to at least one viewing device; a media store for storing media assets; a user interface module configured to receive: i) access credentials for a custom channel producer to access the digital signage system, and ii) access credentials for the custom channel producer to access the at least one media store (210, 212) external to the digital signage system; an authentication module for verifying the access credentials of the custom channel producer to access the digital signage system; wherein the user interface module is further configured, responsive to said verification, to provide access for the custom channel producer to media assets in the media store of the digital signage system; wherein the communication's interface is configured to use the account access credentials for the verified custom channel producer to provide access to the at least one media store external to the digital signage system to determine what media assets are stored in the at least one media store external to the digital signage system; further wherein the user interface module is configured to: i) control a display of a terminal external to said digital signage system and associated with a custom channel producer to display media asset options, ii) detect selection by the custom channel producer of at least one media asset based on detecting selection of displayed media asset options corresponding to the plurality of media assets, wherein at least one of the selected media assets is stored in the at least one media store (210, 212), and iii) receive display parameters selected by the custom channel producer; the digital signage system further comprising: a custom channel controller coupled to the communications interface, the authentication module, and the user interface module, wherein the custom channel controller is configured to produce a custom channel comprising the selected media assets in dependence on said display parameters, and deliver said custom channel to the at least one viewing device.