Alex Bosworth writes about Backpack:
Backpack is basically a list/time management tool. The interesting thing is the zero click interface proposed.
Often you will get an email, or write an email to yourself with an important date to remember or a list of things to do.
If you are sufficiently organized, you might take the trouble to spin up a time/list management tool and enter in the list of items you need to keep track of, or set up your reminders in your datebook app.
But why can’t your email just understand the list of items you want to keep track of, and automatically add them to your list? Why can’t your email (this goes back to my recent post about interop calendars) just automatically mark down on your calendar a time and date referenced in an email?
This is a zero-click interface, and this is what Backpack is trying to get close to. You can just forward your emails with appointments to backpack, and it will automatically set up your datebook with those appointments. The same with todolists, and you can also SMS backpack.