Who is "it"?
I scan a copy of my passport and email it to myself at an internet-based email address (gmail). That way, if needed, I can go to any computer and download and print a copy of the passport. I have never considered doing this for a social security card, and can't imagine why I'd need that. I like this method better than copies, as lost copies could mean personal information would get into the hands of the wrong people.
I did need to use my scanned passport, once, when I was pickpocketed in Chicago. In order to board my flight home, the TSA also reviewed a power bill, magazine labels, Rx labels, and other items I produced with my name on them, but the passport was most persuasive.