Learn English – What’s the etymology of spam when talking about bulk unsolicited messages

I'm partial to the shift key+z typo answer.

If you're typing OMG really fast (cause you're so excited) you're going to slip and hit zOMG, since the < key isn't between shift and Z on most US keyboards.

Outside of any of the other possible origins, the typo is the most likely because it's most easily 'discovered' by small groups of people who are instant messaging each other. Most likely it has risen out of a parallell evolution because of our natural tendencies (as opposed to being invented or "first coined" by anyone).

Essentially, we all invent it ourselves.

I think it is the rephrasing of the more common:

"Stop the Press" or "Stop the Presses":

• is a phrase stemming from the printed news media industry as an exclamation signifying the discovery of the need to change the content of an issue just before, or during its printing.

• Since this meant that the printing press literally had to be stopped or delayed and much of the existing copies of a publication which had already printed had to be discarded - which carried extreme cost, it is a phrase indicating the arrival of extremely significant news or the discovery of an extremely grave error.

• The phrase is common in an idiomatic context, referring to the discovery of significant information and is often used sarcastically.

(Wikipedia)

According to the McGraw-Hill Dictionary of Americam Idioms also:

Stop the Music and (stop the presses):

• (Inf.) Stop everything!; Hold it! (Presses refers to the printing presses used to print newspapers. This means that there is recent news of such magnitude that the presses must be stopped so a new edition can be printed immediately.)

  • John (entering the room): Stop the music! There's a fire in the kitchen! Mary: Good grief! Let's get out of here! "Stop the presses!" shouted Jane. "I have an announcement."