The main issue I've had with this side project is the availability that wasn't so great (as monitoring was conspicuously absent from the start and I never got around to actually setting it up, but I've got plans for it!) and it was eventually caught by spam due to Spamassassin misconfiguration on my part.
So I hope you have a good process for handling spam, and fingers crossed your code crashes less often than mine :)
We started out doing exactly that... send an email with a human readable date to our service, and we'll send you that email back. We also support recurring reminders (every3days@followup.cc), sending attachments directly to evernote (evernote@followup.cc), dropbox, drive, and other things: http://help.followup.cc/knowledge_base/topics/cheat-sheet
We do a lot more now, but that's still our core functionality. We also have a widely adopted Chrome Extension that also makes this a point-and-click operation, but I personally go with the text based approach.
I hear you. We have had a ton of adoption of our Chrome Extension, which also has features like Open Tracking, Send Later and Salesforce Integration. When you click to create a reminder in the extension, we do populate the "bcc" field with the text based version of the email just to show users how it works.
That said, I agree that a simple explanation on the homepage would be useful for people who are just interested in the reminder piece.
I wrote and am operating a similar service at http://remaildr.com
The implementation is open source at https://github.com/Pluies/remaildr/
The main issue I've had with this side project is the availability that wasn't so great (as monitoring was conspicuously absent from the start and I never got around to actually setting it up, but I've got plans for it!) and it was eventually caught by spam due to Spamassassin misconfiguration on my part.
So I hope you have a good process for handling spam, and fingers crossed your code crashes less often than mine :)