1. A method in a computer-based information gathering system for providing demographic visitor information to a participating web site, the method comprising: registering a user with the information gathering system, wherein the information gathering system solicits personal information from the user and wherein the information gathering system maintains a profile for the registered user as computer-readable data stored in a server; detecting, at the information gathering system, a visit of the registered user to a participating web site using an electronic message transmitted to the information gathering system, wherein the participating web site is operated independently from the information gathering system; and automatically providing a demographic information report to the participating web site on a periodic basis, including: developing aggregate demographic information regarding a plurality of registered users who have visited the participating web site over a predefined period of time using the detected visit; providing the aggregate demographic information in the demographic information report.