I keep getting spam to [email protected] (which I used for a dodgy signup wondering if spammers would react differently to a vaguely official looking address) claiming to try to sell me electric bicycles. I don't really understand why someone would ever want to buy nore than one or two electric bicycles or why they'd buy them from a spammer. The message is written in a way that could look like it was merely misdirected. This sounds like a message used to test mail servers etc as mentioned in the article.

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Entirely separate comment: this type of broadcast channel is used in the newsgroup alt.anonymous.messages, though in there, the presence of a message is obvious.