Data trails in my books!

I had bought several novels at the used book store around the corner a few months ago. When I finished one of them a receipt fell out. While that surely isn't anything out of the ordinary I found it interesting nonetheless since it was (expect for one kink at one corner) in pristine condition and entirely readable after about 15 years and 334 days - take that thermal ink! The lovely dot-matrix printing has a very nice blue-magenta color and tells me a few details about that person who originally bought that book:

He or she paid on May 4th 1991 at 15:11 with a twenty dollar bill for three paperback books in a Louisiana Waldenbooks. Since my book was released as a cheap paperback in May of 1991 this seems quite probable: the original customer apparently found something he liked on the 'New Arrivals' shelf. The person had a preferred reader account with them, a program that was started just the year prior but was discountinued in 2004 according to answers.com, and the account number is printed in the clear. Had that program still been active this might have revealed more information about that person.

A quick googling did not return any information on the other books the person had bought. The numerical identifier on the receipt seems to be the ISBN number with the group prefix removed but since my book was group 0 I don't know if they adjusted the checksum for the others (note to self: read up on those). However, even with that the full ISBN number nothing turned up, not suprising since paperback copies are seldomly found in the Library of Congress nor does the majority remain in circulation for that long to pop up on Amazon. Contacting the publishers through their infix in the ISBN would probably give that answer.

The receipt itself is a nice reminder of how receipts used to look like, when compared to what one now gets in advertising, disclaimer and revoked consumer rights on a piece of paper..or two..or three.

But why this post? I think it makes a very important point about the data trails we leave behind every day. I'm not even talking about some stores that print credit card numbers in the clear but even this otherwise worthless receipt gave me an awful lot of information about one person. I might not have any way of tracing this particular receipt back to the original owner but when one looks at our current pace of leaving stray pieces of information all over the place in our modern lives - especially the Internet - we are probably in for a lot of hurt, should somebody have enough criminal energy to want to ruin your day.

If I come across a scanner anytime soon, I'll amend it.