Internet Marketing: Link Supertrick
Make sure every outbound link that is visible to the public is put in a "new window." This means that when someone clicks on a link that takes him or her out of your site, a new browser window opens and your site is still running in the background. The visitor never actually leaves your site. This new window can be set to open slightly smaller than a regular window, which alerts the person that your site is still available in the background.