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 from a plurality of users communicating on a communications system, the data including personal characteristics about the users; analyzing the personal characteristics to determine a plurality of groups of personal characteristics; clustering the users into closely matched groups respective to the groups of personal characteristics; generating a plurality of activity information about each of the users in the closely matched groups, respectively, the activity information including a physical activity; and 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, wherein at least one of the above steps is performed using a program executable by a processor of a computer.