million dollar idea: centralized electronic receipts

I can't get past the fact that if I buy an earth day sticker from ANY store, I am going to get a piece of paper (in many cases nearly a 10 inches long for one item) that will only end up being filed, trashed or recycled. If you file your receipts you are probably more organized than I am, if you don't file them then the chances are that the paper receipt will be added to the already overwhelming amount of refuse that we as a species have been stockpiling.

***** If I owned a business this is what i would do *****
Instead of wasting the money and paper it takes to issue a foot long receipt for a stick of gum, create a centralized repository for all a person's receipts.

Each person can have an account that the eReceipts can be sent to from various participating companies. It seems like it would work best if eReceipt accounts could be tied either to a preferred customer card account or a credit card.

Benefits:
* electronic filing/management
* can't lose receipts
* easy querying for old receipts
* trending
* paperless product returns
* better management for RMA numbers
* NO PAPER WASTE
* NO MONEY WASTED ON PAPER

Precautions:
* user registration is anonymous. (the username is a number or hash)
* each user creates a password with strength enforced.
* preferably there will be a form of 2-factor auth (not realistic but a thought to kick around)

PROBLEM:
* if a person's profile is hacked it presents a pretty significant breach or privacy. (anonymous registration should help prevent some of this)
* companies have to participate and there will probably be some implementation costs incurred to offer this system instead of or in addition to their existing paper based systems. (but how much are they shelling out on paper and printer maintenance/replacement?)