Data you can download, identity is hard to change. For example: I can download all my mail from gmail (using POP or IMAP) regularly. If I lose the account I st

Data you can download, identity is hard to change. For example: I can download all my mail from gmail (using POP or IMAP) regularly. If I lose the account I still have my mails. I can't change the mail amazon (or whatever other site) knows about unless I have access to my gmail account (I realize you can probably talk to their customer support but it doesn't scale well at all. I have about 120 different logins using my @gmail.com address...).