Two features Yahoo Mail has that Gmail does not (officially, anyway)—unlimited storage and "AddressGuard" disposable addresses—make it the ideal solution for keeping an online repository of important documents. Blogger Bert Webb does just that. He scans paperwork like birth certificates, warranties, copies of insurance cards and tax documents emails them to a disposable Yahoo Mail address set up to automatically filters them into a "Docs" folder in his email account. Of course, using Gmail's "plus sign" trick and its virtually unlimited storage, you could do the same there, too.
Turn your Yahoo Mail Into a Document Storage Lockbox! [via : Lifehacker - Open Loops]