I don't mean this to sound as if it's a complaint, but in order to describe the idea, I need to explain why this idea's occurred to me.

Late yesterday afternoon, I looked at my tasks, and I noticed that there appeared to be a very huge chunk of them missing. I do not remember doing something so nonsensical as deleting them, but as they're not showing up in "completed", etc., it suggests to me that's what's happened, unless it's merely a system display bug of some odd sort.

I contacted RTM through their contact form, and sent several e-mails to them as well in the evening and morning. As of now, approximately 16 hours later, I've received no response.

Given the difference between RTM's home time zone and the North American and European climes where a lot of its users are, and given the no-doubt busy schedule of the RTM team, it might be useful to have this process automated.

Say, have a button in the Preferences marked "Revert to last saved state." Require the user to doubly confirm his or her intention, do whatever safety check is needed. And then, when this button is hit, have that user's setup reverted to whatever the system's last backup was.

Alternatively, RTM gives lots of ways of users to export their data out of RTM, but no way to import that data back in via the same formats. It might be nice for RTM to either accept imports in the same format that it exports in (ics, etc.), or to develop its own specialized backup file that it would accept in order to restore a user's account to a backed-up state.

These above tips would put the backup process under user control. I think that with allowing users to backup, it would be wisest to make it available to all users, but if need be, I imagine it would be a powerful attractant for the pro-user package.