Better Than a String Around Your Finger

Remembering to write someone back is all well and good, but remembering to remember when you need to -- that's a whole different hassle. will send you email reminders based on when you actually need to produce a follow-up message. A free version lets you set 50 follow-ups per month; plans priced at $2, $5 and $9 per month offer more reminders and more features.