PatientSite is a secure, personalized messaging system serving BIDMC and affiliated sites. It allows patients to communicate confidentially with their physicians and the physicians' staff via the Web. Patients are eligible to enroll in PatientSite if one of their physicians has agreed to use PatientSite. Data in PatientSite are encrypted and password protected. Patients register online, and receive passwords from administrators at their own practice site in order to confirm the patient's identity. Patients and clinicians must use a confidential password to obtain access to the system. To alert PatientSite users to the presence of a message, PatientSite sends users a traditional email message that they have a PatientSite message, along with a link to the PatientSite Web portal.