1. A method for sharing data between a plurality of users in an online group on a communications system, comprising the steps of: receiving data, using a computer, from a plurality of users communicating on a communications system, the data including personal characteristics about the users, the personal characteristics including one or more of: an interest, an occupation, a marital status, an age, an education level, an experience area, and a goal; segmenting the personal characteristics and generating aggregate personal characteristic data pertaining to targeted dispositions of users; analyzing the personal characteristics to determine a plurality of groups of personal characteristics, using the computer; recording availability of the users for communication and computing overlap of the availability for the users; clustering the users into closely matched groups respective to the groups of personal characteristics, the users being clustered into a maximum number of the closely matched groups; after the recording of availability of the users and the clustering of the users into closely matched groups, generating a plurality of activity information about each of the users in the closely matched groups, respectively, the activity information including one or more of: a physical activity, a location, and a time of day; next, allowing access to the users in each of the closely matched groups to the activity information about other users in each of the closely matched groups, respectively, using the computer; recording behavior of the users toward respective goals and computing common characteristics for the users; computing a social affinity for a group of users of the users based on the common characteristics and the overlap of availability of the users; generating a projected success rate of a behavioral change for each of the closely matched groups and the users in the groups, respectively, based on an analysis of the activity information; and generating a suggested activity change to achieve a behavioral change for a closely match group and the users of the closely matched group based on an analysis of the activity information.