Schneier on Security

Useful, but you're vastly more likely to use a Squid cache. You actually have just now, because Wikipedia is powered by them.

http://en.wikipedia.org/wiki/Squid_cache

The Wikipedia entry appears to lack an entry for Submillimetre Astronomy in their 'uses' section.

Did you mean "Submillimetre Gastronomy"?

and the Squid cache own site http://www.squid-cache.org/

The Mag SQUID actualy has had a lot to do with security in the past.

You used to find them in various sonar bouys and other equipment used during the (not so) Cold War to find SSNs etc lurking benieth the seas of the world.

In the UK some people may remember the Nimrod Aircraft it had a range of sensors it could deploy with quit a few SQUID in them for detecting Rusian (and U.S) Subs with quite a high degree of success.

If room temperature superconductors become reality, the use of SQUIDs will have some important security ramifications due to the lower cost of maintaining the SQUIDs in a superconducting state. Arrays of SQUIDs could be used to track all metal objects in a large area. Wireless sensor networks with SQUID sensors could do the same. Maybe such systems could track the electrical fields generated by people? Brain activity mappers may become inexpensive enough to use in interrogations to get some insight into peoples intent. I've heard that the sensitivity of SQUIDs is similar to hearing a whisper on the other side of the world. What might that mean for personal privacy? To national security? If we use SQUIDs in planes to detect subs, how about SQUID arrays to track ALL the vehicles in an opponent country? Or track all vehicles in your own country?
Maybe the future will be plastic.

Dang. Just when the wife had finally convinced me to drop my collection of aluminum foil hats in with our collection of Indian rupees, old pennies and other such headed for the metals-purchase chap ...

I still have a weakness for meta-jokes no-one is going to get. Normally this manifests as axiom-of-choice maths jokes, but to physicists I occasionally get to say:

A whale swims up to an octopus it knows with a broken superconducting quantum interference detector on its back. (The whale had the broken superconducting quantum interference detector on its back, not the octopus.)

The octopus says "What's this?" and the whale replies "Here's the sick SQUID I owe you."

@Jackv

That joke is almost as bad as the,

"Why did the cat slide off the roof joke"

For those that do not know look up what the coeficient of friction is called.

and then say (not read),

"because it had a small mu".