Have you heard about dead drops? Neither had we. Basically it's this "underground" thing where someone sticks a USB flash drive in some concrete sticking out of a building somewhere, and you can bring your laptop there and plug into it and share files completely offline. Think of it like an anonymous, pre-internet internet, if such things as flash drives existed back then.

This all began three years ago in New York with artist Aram Bartholl installing five of these dead drops around the city. He followed that up with a DVD dead drop that was commissioned by the Museum of the Moving image.

It's all anonymous and, ostensibly, safe, and dead drops are meant for people just to share their "favorite" stuff.

According to the map here, there are currently two dead drops in San Francisco: One at Noisebridge at 2169 Mission Street (between 17th and 18th) with 300 GB; another at Instructables at 82 2nd Street (4 GB). Then there are a couple more down on the peninsula, in San Mateo, Redwood City, and some in San Jose.

See the how-to for installing your own below. We look forward to this catching on, and are frankly surprised that it hasn't. But then again, I guess sharing things from your phone is a whole lot easier.

Also, a video in which Bartholl talks about the "future of offline filesharing" in 2012.