Email reminder services work anywhere your email works. For almost as long as there has been email, there have been programs that would automatically send email reminders since the function is relatively simple to program, and immediately useful. These early services were typically used to send reminders of birthdays, anniversaries, and other important events, although some systems could also operate on a daily calendar and send an email a few minutes ahead of each meeting throughout the day, often with a command to trigger a bell sound.
Modern email reminder services are accessed over the Internet through the web. These sites require you to register your email address and set up an account, often free, and provide an easy configuration screen to set up your reminders. A reminder can be a one time event, or sent weekly, monthly, or yearly.
Resources. The following sites provide email reminder services:
Lists of reminder services: