Well, they are programmers, I think they are more than conscious about how we (others too, but especially programmers) feel about that! Also, we can always pest them back with auto response filters[1] :-)

[1]: A Croatian (I'm Croatian, too) website made me submit my email for a Web purchase, but they started sending newsletters they have no unsubscribtion mechanism, and they send the newsletter from <newsletter id>-newsletter@..., which I could filter and send to spam (which I also do) , but instead, I forward the email back to them and also send a reply that I'd like to stop receiving these emails. Ironically, they asked me on a few occasions to stop emailing them, I simply respond with the same reply they sent me when I asked to be unsubscribe: "It's automatic, there's nothing I can do about it." There's always a way to fuck with those who try to fuck with you. :-)

Sounds sort of like a quine e-mail.

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