"books you checked out at the library. No one was all up in
arms over that"
..because compiling that sort of data wasn't feasible. Computer
database searches have changed that. In fact, now someone -can- find
out what books you've checked out. In minutes, not weeks, and with
almost no labor cost.
Example. You dated a girl when you were young, and it ended very badly.
She's married now and you don't know her name, but you know her
brother's name. Facebook: found her brother in 30 seconds. She's on
his friend list, there's her name. Go to her FB page. Her friends list
- there's her son's name. His FB page: brags about being a car
salesman, in a town two miles away. In less than a minute you have a
real physical connection to someone for whom you've harbored hatred for
30 years.
All this computer data is making it impossible for anyone to "blend in"
and all it takes is for someone to take a mild interest.