> The other half, however, are less pleasant to read and mostly contain a colorful mixture of swear words, conveying the basic message that they’d rather not be contacted in the future.

The fact that a full half of the people who bothered to respond were so offended by your actions that they took the time to swear at you might be a clue that spamming your customers is not a good way to generate positive feedback.

I recently bought tickets from Ticketmaster and stupidly gave them my real email address instead of my spam email, thinking perhaps they would send something I would need to get my tickets. I think I had to unsubscribe from five separate lists to get them to stop sending me garbage.

> I wish that they’d just click the “Unsubscribe” link in the email, since that’s what it’s there for after all

Tell you what, every day you send a spam bomb, spend 2 minutes staring at the wall for each and every person that clicks the Unsubscribe link. Then you'll have some understanding of how much time you are wasting for your potential (now probably ex-) customers. I mean, that's what the wall is there for after all.

In short, fuck spammers.