1. A method of recommending entities to a user for inclusion as content contributors for a datastream using a networked computing system comprising: a. automatically identifying with the networked computing system an information contribution provided by each of a base set of content contributing entities selected manually by the user in a white list; b. in response to a user request for suggestions for a first additional content contributing entity for inclusion on said white list, automatically comparing with the networked computing system content contributed by said base set of content contributing entities with content contributed by a plurality of candidate additional content contributing entities; c. automatically recommending to said user with the networked computing system a recommendation that one or more selected ones of said plurality of candidate additional content contributing entities be included or excluded from said white list based on a measured overlap in information content between said first additional contributing entity and said one or more of said plurality of additional candidate content contributing entities; d. in response to the user selecting one or more additional content contributing entities intended as information sources for the datastream, generating a visual display output for the user indicating graphically: i. a first predicted change in coverage in the user's datastream for first content associated with a first topic based on adding or removing one or more first content contributing entities; and ii. a second predicted change in coverage in the user's datastream for second content that is not associated with said first topic based on adding or removing said one or more first content contributing entities; wherein the user is presented with a visual diagram of changes predicted in the user's datastream as a result of content contributions of a user selected content contributing entity.