Like some elaborate spy communications network, an art project that began three years ago by prompting people to embed USB thumb drives in structures has caught on like wildfire.

Dead Drops, as the project is called, now has more than 1,200 locations worldwide where anyone with a computer and a USB port can anonymously plug in and upload or download files -- sharing who they are or what they care about or love.

The premise: cement a thumb drive into a wall with just the port protruding, and leave its location with photos in the Dead Drops central database.

A more typical Dead Drops location. In the wall of a building.

According to the creator of Dead Drops, German artist Aram Bartholl, the project is a way to "un-cloud" file sharing -- that is, remove it from the Internet in a time when governments are spying on the online public.

"Dead Drops is an anonymous, offline, peer to peer file-sharing network in public space," Dead Drops' manifesto states.

While the first Dead Drops participants tended to be music bands sharing their tracks, the project has grown to include thumb drives with movies, games, comics, and television shows. Others share poetry, family videos and photos or even art projects.

Bartholl started the Dead Drops project in 2010, while an artist in residence at the Eyebeam Art and Technology Center in Manhattan. He began by embedding 5 USB thumb drives in the walls of buildings around New York City, posting images of the locations on the photo-sharing site Flickr and an Internet home page for the project.

By word of mouth, the project began building momentum; within six months, it had spread from the U.S. to Europe.

Today, there are 1,218 Dead Drop locations worldwide, according to the project's database. The database page offers a the name of the thumb drive's location, which sometimes simply includes the participant's pseudonym, the address (including the city, state and country), and the size of the USB drive.

"It's about making people think about how we live online and how we live as social beings," Bartholl told Computerworld today. "It's to have people think about relations, what we do online every day, and how things have changed over the past 10 years [since 9/11]".

"And, it somehow turns the whole building into a drive," he added.

A Dead Drops location in Beijing, China

Bartholl's idea was based on an espionage method used by spies to pass items between two people using a secret location. The Dead Drop meant the two people never met face to face.

While Bartholl instructs participants to embed the flash drives in building walls, the locations over time have become as varied as the data stored in them. Dead Droppers now embed drives in walls, parking lot asphalt, bridge abutments and deep inside forests. One Dead Dropper embedded one in a palm tree on the campus of California Polytechnic State University in San Luis Obispo, Calif.

"I think it's attractive for large groups of people because it has the air of spying but also geo caching," Bartholl said. "It's about making people think about how we live on line and how the Internet is changing the whole sphere of how we live as human beings."

Some Dead Drops locations are not easy to find, as this one at 17301 Skyline Blvd, in Saratoga Calif. proves.

Some Dead Drop locations are in the heart of cities like New York, others are in the ruins of buildings in remote fields. Participants have gotten as creative with the locations as they have with the data they leave there.