I've seen this phrase used quite a bit especially related to conspiracy theories and the like. What exactly does it mean?

it kind of means your calling someone paranoid, or something odd happens and you tell someone you know thats paranoid (or a conspiracy theorist) to put on a tin foil hats.

it is a joke, somewhere in a show or something, they put on tin foil to keep there brains from being scanned or something.

and when people talk about conspiracy theorists ( or joke about them) they often talk about them being scared and putting on the hat to protect themselves from aliens and such.

its often referenced in media.

im not well versed in the subject and thats about the best answer i can give.

http://scienceblogs.com/startswithabang/upload/2009/04/weekend_diversion_do_tinfoil_h/tinfoil-hat.jpg

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

Wikipedia knows all...

Prevent government mind control, duh.

Bah, tinfoil hats won't help. You need a Faraday's Cage suit :hehe:

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

Sayin' you don't have yours yet?

[edit]
Heysoos H. Keerist, how ninja'd can I get...

Conspiracy theorists with a laughable paranoia wear tin foil hats (the best in mind control protection and quite fashionable!). Its rampant these days.

Be prepared for the most bat sssss insane ideas to ever be uttered... Examples can be seen on above top secret forum.

At one point, Western owners of the Russian brand of motorcycle called Ural used this as an inside joke, wearing tinfoil hats at their gatherings. http://www.sheldonaubut.com/narma/narma/press/WSJ.htm

Don't tell them what it means!

If you are looking for some serious lulz, or just to be downright horrified, visit this website!

:P

I remember how horrified I was when I saw my nick mentioned in a thread in the UFO subforum... Not even registered there... Also that thread about low electrical current being used to self treat AIDS wonder if that guy is dead.

It keeps the Government out of our mindsss man. They want to bring us downn.
And they look pretty cool.

There was an old movie with a guy in it, I'm pretty sure it was a comedy, could have even been an old saturday night live skit...anyway.. the guy was paranoid about aliens reading his brain waves and made a tin foil hat to prevent it... I've searched youtube and couldn't find it. If someone remembers this please post it.

Tinfoil hats have been around way longer than SNL. They've been around since the 20's, and there wasn't even TV's then.