One of the most powerful ways to develop web site traffic is to enable your users to share their content through your web site with others–to create community around user generated content.
Many of the fastest growing web sites of all time did this (or do it now): MyFamily.com, eBay, GeoCities, Xoom, Homestead, MySpace, Epinions, Hotshots, LinkedIn.com, Meetup.com, Friendster, and more.