Most email programs available can be classified into 2 categories
1) web based email - a user account has to be created with a password. All relevant data is stored online in the database of the website. Email notifications are sent on important dates . The user is also notified when he / she logs into the account.
2) Desktop email client - software has to be downloaded from the website and installed on the desktop or laptop. The information stored usually remains confidential since only a limited number of people have access to a home computer. However, the reminder software may contain spyware or some features may be available only in the paid version
Both these options have their own advantages and disadvantages