A person who refuses 21st century technology tracking and other identity filing-stealing systems that normal folk use in daily life. This person wants to live a life that is as hidden (blank) from existance as possible.
The 'blank' wants no attention from 'Big Brother,' 'the establishment,' 'the man,' 'the system,' or whatever global totalitarian watchdog in which you believe.
This person refuses to: use credit cards, use internet identity systems, vote, and probably keeps only a PO Box. Blanks might refuse to pay taxes, hiding from IRS, FBI, and only does business in cash. Blanks rely on pre-computer business methods and probably own lots of books instead of being wired in like everyone else.
According to the Max Headroom TV series cyberpunk universe (1987–1988): A blank is a citizen not indexed in anyone's database. (wikipedia)
"The Blanks" (1987) is also an episode of the series.
Don't confuse this group with illegal aliens, criminal sleeper cells, or gangs that are also outcasts from normal society. Blanks just can't stand the hypocracy of society and the control it has over most people, and they won't jump through the hoops and give away their freedoms like the rest of us sheep.
Meag: Really? I thought you guys were friends?
Laura: Yeah, me too. I guess he just didn't want to talk to me.