The Internet might transform the way in which health information is communicated to patient and general populations. Understanding differences in usage patterns will be critically important to ensuring the successful distribution of health information. The present study presents early data on the use patterns and predictors of use of a Web-based intervention in a population-based subsample of women aged 18-74 in King County, WA. By three months over half (51%) of users had logged into the website, using multiple components. Predictors of use by three months included employment, perceptions of health and mental health scores. These data have implications for how to conduct Web-based intervention research and for individuals that may not benefit from such interventions.