The thing about replacing e-mail is that is isn't just a todo list, for many people it's just a receipt box - the thing I keep all my notifications that I bought stuff from amazon. For others, it's still the primary means of business communication. My work e-mail is largely about communications, with a todo element to it and unfortunately some file storage too. My "home" e-mail is completely different. It's where I g…
There's a good startup idea right there! Sign up on receiptbox.com and give it my email username/password (or maybe some sort of oauth token). It periodically scans my email and looks for receipt emails from well known e-commerce sites. It knows how to parse them and pull out the relavent details (like TripIt does for travel stuff) and it builds a builds a nice searchable catalog of all my receipts.
I would sign up for this tomorrow if someone on here goes and builds it. :)