SPAM..fullform ?

I cannot vouch for the authenticity, but the most interesting explanation that I encountered was in relation to Monty Python's Flying Circus. I know that this sounds a little absurd, but the famous Spam sketch from Monty Paython involved the cafe owner perpetually droning on about spam despite the insistance of "I don't like spam", along with that wonderful viking chorus of "Spam spam spam spam" in between. It has been suggested that this was used as an analogy for those annoying emails that keep being repeated over and over again no matter how much you say "No".