New Scientist is reporting that a massive database culled from the public profiles of 210 million Facebook users has been destroyed before its anticipated — and controversial — release to researchers.

Pete Warden, a former Apple engineer, reluctantly deleted the data after Facebook threatened legal action, saying he could not afford to fight a lawsuit. He said Facebook was not aware that such information was available and that the flaw is being patched.

His handiwork included a “social graph” and a colorful “visualization” that revealed connections among all FB users, which New Scientist writes “would have been a powerful research tool for social scientists and others interested in how people interact.” That raised privacy concerns.

His map divides the Facebook nation into regions with such fanciful names as “Stayathomia,” “Greater Texas,” “Socialstan,” “Mormonia,” “Nomadic West,” “Pacifica” and “Dixie.” Read about the characteristics of each region.

Here’s some of what he wrote in explaining his decision to wipe the database:

Despite the bad taste left in my mouth by the legal pressure, I actually have some sympathy for Facebook. I put them on the spot by planning to release data they weren’t aware was available…
So what’s the good news? From my conversations with technical folks at Facebook, there seems to be a real commitment to figuring out safeguards around the widespread availability of this data. They have a lot of interest in helping researchers find ways of doing worthwhile work without exposing private information.

Separately, Warden writes about “the unknown marketing databases that know everything about you” — and that are for sale to anyone.