I feel passionately about this passage:

Good. Unsubscribes are a good thing.

Think of it this way: someone who unsubscribes is just as valuable to you as someone you never send email to.

Unsubscribes clean up your database. People who were never going to buy from you should always be left out to pasture. If they want what you are selling, they will make their way back to you.

I believe in unsubscribing so strongly, I remove email addresses from my own list every month to keep things efficient.

It’s not something to be scared of, it’s something to embrace!
Unsubscribes mean less fluff in your list, so you are serving content (not just sales crap) to people who are genuinely interested.
Interests change over time, so no doubt these people will float in and out of being interested and disinterested.

Companies really need to get their heads around this concept.
Hoarding people’s information is such a fruitless venture.