OK so to be clear- there is data, and then there is Information. Data is countless different places where little bits of your internet life are stored, and sometimes stored carefully. ( Ok probably not carefully...)
Sometimes this data is benign and really doesn't mean crap. Aka Bob spent $16 at the Quikmart.
Other times, the data is very specific and details lower level information. Bob bought 8 back issues of Sassy Gent magazine at Quikmart, for $10. He also bought a $6 tube of Smooth Lube at the Walgreens, a pack of Ramses Sphinx giga-rib condoms and a map of a neighboring state for $19. Oh, and there was a gas fill-up for $26 at the Loves truck stop and a $9 damn Mexican-like cotton blanket. ( you know the ones...) Doesnt matter the source, image scanned, direct entry, etc. its in there.
I could go on, but the fact is that your retail life maps your world in greater detail than you could ever imagine. This without any chicanery or cleverness on behalf of some Letter Agency. Buying pregnancy test kits ? Gotcha. Here's some diaper, parental paranoia ads, etc.
So, as far as Information goes. Anyone who has spent time in this area ( digital data realm) can tell you that being able to combine seemingly unrelated but comparable data can turn a bunch of benign information into very personal and valuable Information quite quick.
And it is disturbing how quickly we collectively feed the gaping maw of Big Data.
Some little bits of info mean nothing but combining it all is Power.
Also, the cows out of the barn. All you can do is minimize your footprint.