I believe one of the purposes of euphemisms in the world of eavesdropping / wiretapping is to find the metaphors which are used to mean drugs or violent actions.

For instance:
a) I was on a jury trial where the person was charged with hundreds of pounds of Cocaine, and the prosecutor said the messages were for "White Shirts"
b) Some terrorists were anticipating an attack, and they said the "wedding cake is ready"

I believe both of these count as metaphors (as opposed to similes which use "like" or "as"). Although this is not iron-clad ("John has a long moustache" was the code phrase for the invasion of D-Day by the Allies against Nazi Germany), it is an "out of context" remark that would slip through a mechanical search for key words "oil", "gold", "corn", "soy beans", "money", "coke", "grass", "weed", which could be scanned by a computer for later review by a person, which was the technology in use some 30 years ago by the NSA (National Security Agency) which ostensibly only monitors foreign traffic, but who knows under the Patriot Act of 2001, which is still not fully made public.

In other words, if the government had all the metaphors used to denote a victory in Iran for building a nuclear bomb, or testing its product, or for reaching a supply of the critical mass of uranium, plutonium, then those would be the metaphors one (or one's computer) would most likely search for.

As a comedian once said: I know that when I ask my friend for "circus tickets" for $50, I better not get tickets to the circus.

I think that the increase in variations of a source relates to Darwinian evolution. For instance, corn is from the Americas and moved to Europe after Columbus. And if you look at the varieties of corn in the USA there are a certain number. But if you look at South America, there are many more types of corn. http://www.sciencedaily.com/releases/2008/06/080627163156.htm

The greater amount of variation indicates the origin.

This is also true for genetics. There is the greatest variation of genes in Africa, and fewer, say, in subset migrations, e.g. Greenland. ["Africans have world's greatest genetic variation "] http://www.msnbc.msn.com/id/30502963/ns/technology_and_science-science/

LOL. Literally. And I'm by myself. And I'm anti-guns / pro-gun-control. But, well done,sir.

I think the xkcd cartoon is cute, especially for us techies. On a different, related matter: In 6.251 (MIT's class on operating systems, circa 1970), the professor (Donovan) had students submit the punch cards, and the program he wrote would evaluate them with "Yes" or "No". Except one of the results was "Maybe", so he gave that student an "A". The point is: sometimes cheating (we called it "hacking" back then) required more knowledge than the task at hand. I emphasize the word "sometimes", since when other people use the hacks, they may not learn anything, although they may be more productive, which I think is the point of using artifices or helpers (whether it's a slide rule from my youth in engineering, or using canned chicken broth instead of making it myself from scratch in a cooking recipe) is that often you can reach higher heights by standing upon the shoulders of others, as Newton said.

Well, I do have to say I'm disappointed, since I had the same problem with Norton: once with my PC -- where I don't mind paying $100 since my stuff's so valuable, and then with a friend who had a virus, where he just wanted the thing working. With my friend's PC, the virus stopped Norton from even using their logmein123 program. And we were kept on hold for hours -- literally. I expected more from Norton (sigh).