Effective techniques to encourage colorectal cancer screening in underscreened populations have included social support interventions and e-mail reminders from physicians. Personalized e-mail messages to promote colorectal cancer screening within social networks could be even more effective but have not been studied. The authors interviewed 387 e-mail users, aged 42-73 years in Georgia, Hawaii, and Massachusetts. Participants were asked to edit a sample message in which the sender shares a recent colonoscopy experience and urges the recipient to discuss colorectal cancer screening with a doctor. For those reporting willingness to send this message, changes to the message and suggested subject lines were recorded. Edited text was analyzed for content and concordance with original message. The majority of participants (74.4%) were willing to e-mail a modifiable message. Of those willing, 63.5% edited the message. Common edits included deletion (17.7%) or modification (17.4%) of a negatively framed sentence on colon cancer risks and addition or modification of personalizing words (15.6%). Few edits changed the meaning of the message (5.6%), and even fewer introduced factual inaccuracies (1.7%). Modifiable e-mail messages offer a way for screened individuals to promote colorectal cancer screening to social network members. The accuracy and effects of such messages should be further studied.