Being reminded based on where you are

[mehdi]

The system should also be able to learn how often you buy milk and suggest that maybe it's time to buy it now.

True. The system needs a little bit more of machine learning from what i originally imagined.

The truth is one should know intuitively and from one's lists what to do where; one ought not to rely on software to "remind" what to do where.

I agree this might sound over killing, but if you do the analogy between lists and reminders, you could argue that one ought not to rely on software to know what are his todos. How many time did you do a list, and forget about it? The list (and its items) should come to you in the right context. That's my opinion.