I’ve been thinking about this for a while, now, and I can’t figure out why I’ve never seen it implemented anywhere.
It would be great to have a reminder or to-do list that made use of the location information available to it through GPS.
This would allow me to create reminders for when I was in specific places. For example, a really simple use case would be:
"Next time I’m in town, remind me to pick up a birthday present for Bob’, or:
“When I’m in the supermarket, remind me that I need milk”.