1. A non-abstract machine system that is structured to automatically present as first presentations to a first user of the system, user-acceptable invitations to join in on telecommunications-mediated information exchange forums and/or to automatically present in the first presentations to the first user, user-acceptable suggestions of additional telecommunications-conveyed informational content to investigate, wherein the presented invitations and/or suggestions are based on content that the first user is presented with and are based on automatically repeated determinations by the machine system of what specific sub-portion or specific sub-portions of the presented content the first user more recently centered his or her attention upon, wherein the automatically repeated determinations regarding attention are carried out transparently by the machine system without need for diverted centering of attention by the user directed to aiding the automatically repeated transparent determinations by the machine system, the machine system comprising: a presentation format controller that determines or controls at least one of: whether or not a given user-acceptable invitation or user-acceptable suggestion is presented to the first user; when a given first presentation is presented; what order of presentation is used for multiple ones of the first presentations; at what rate multiple ones of the first presentations are automatically presented; and in what format are the given one or multiple ones of the first presentations automatically presented to the first user; wherein at least a portion of the machine system includes a data processing machine, and wherein said automatically determined and more recent centerings of attention by the first user occurred no more than at least one of: 3 hours prior to said presentation of the first presentations to the first user; and a determined time duration prior to said presentation of the first presentations to the first user, the determined time duration being determined based on a currently active profile characterizing the first user.