Why spam?

The word spam has recently been added to our language. Each one of us recieves daily tons of unwanted mail. But why "spam"? Who baptized this phenomenon?
SPAM, was the label of a conserved meat can made in England, which was very popular in the army during the Second World War. It's circulation was so overwhelming that very soon people got really tired of it.
During the 70's, Monty pythons made a scetch on their show (entitled "Spam") where a couple was trying to order a spam-less meal in a restaurant-with no success. The menu listed: egg and bacon; egg sausage and bacon; egg and spam; egg bacon and spam; egg bacon sausage and spam; spam bacon sausage and spam; spam egg spam spam bacon and spam; spam sausage spam spam bacon spam tomato and spam
With unbelievable foresight, the Pythons made it clear that the words Spam! Lovely spam! Wonderful spam! wont be heard again in our time...