Spam is a fine spiced ham product made by the wonderful folks at Hormel Foods . Email spam, which is now a more serious problem than Usenet spam, is similar in concept but different in execution.
Email spam is usually easy to recognize, but harder to define.
There's nothing wrong with bulk mail, with unsolicited mail, or for that matter with commercial mail, on their own. I welcome those. Incidentally, notice that there's no mention of forged addresses here. Some proposed bills claiming to try to outlaw spam have only concentrated on the forgery aspect, which is common. Forgeries are symptom of spam, not a defining characteristic.