Users are increasingly sharing intimate details online with little concern for who might be viewing their information. Some users are even willing to share personally identifiable information, such as real names and photos, together with medical records with the site. Almost any information users post online can spread so quickly that they can’t feasibly withdraw the information if they change their minds about sharing it. For example, a user might post a psychiatrist’s notes about his or her serious mental illness to get feedback on the condition or treatment. Then, another user might save that information
and either communicate it to other people or post it on the Web. Sooner or later, it could reach the inbox of someone the user really doesn’t want to see it, such as an employer or insurer. Furthermore, users typically have no control over retention periods for their shared data, which could live forever on the Web.