If you like the reminder functionality but don't want to switch to yet another mail application on all your devices: https://followup.cc https://followup.cc is

If you like the reminder functionality but don't want to switch to yet another mail application on all your devices: https://followup.cc https://followup.cc is a great service, you can also try my own (less sophisticated but FOSS) implementation at http://www.pfalke.com http://www.pfalke.com