1. A graphical user interface for a wireless mobile device having a gesture sensitive display through which the user interacts with the interface and further having the capability to wirelessly communicate via a remote host computer system with other mobile devices with like interfaces for enabling those mobile device users authorized to participate in the system to create, to join by acceptance of an electronic invitation received from another mobile device, to organize, to manage and to separately communicate with a multiplicity of affinity groups, said interface comprising: (a) a scrollable home screen for visually displaying to the user in separate gesture sensitive blocks the individual names of those affinity groups the user created and those the user joined and at least a portion of the most recent message received in each of said affinity groups; (b) a gesture sensitive icon on the home screen for opening an affinity group creation screen to enable the user to create and to assign a name to a new affinity group and to specify other mobile device users to whom to send electronic invitations to join the new affinity group; (c) the interface being responsive to the user creating a new affinity group for adding to the home screen a new gesture sensitive block visually displaying the name of the newly created affinity group; (d) the interface displaying on the home screen an invitation icon indicating that the user has received an unanswered invitation to join an affinity group; (e) the invitation icon on the home screen being gesture sensitive for opening an invitation reply screen to provide the user predetermined information about said invitation including its affinity group name and for enabling the user to accept said invitation; (f) the interface being responsive to the user accepting said invitation on the invitation reply screen for adding to the home screen a new gesture sensitive block visually displaying the name of the newly joined affinity group; and (g) the affinity group identifier blocks on the home screen being individually gesture sensitive to open respective affinity group message screens for viewing messages electronically received by the user from others in said affinity groups and for enabling the user to prepare messages for electronic transmission to others within said affinity groups.