Adding you as a connection on LinkedIn, doesn’t mean I want you to add me to your newsletter.
Giving you my email after buying your product online is only because I want a receipt, not to add me as a member of your mailing list.
Leaving a comment on your blog, doesn’t give you the right to subscribe me to your newsletter.
Creating an account for your website doesn’t give me the ability to see this invisible checkbox that magically subscribes me to your monthly email at the same time.
Finding my email online doesn’t implicitly give you the freedom to send me your newsletter.
Accepting my business card is not an agreement on my side that I want you to sign me up for your regular publication.
I can write about this in many other ways; it will still be true. If I didn’t explicitly specify, either to you in person, by subscribing myself, or by checking (or should I say, leave checked) the checkbox, there is no way, I repeat, NO WAY, you have the right to subscribe me to your newsletter. Email is my primary way of communication, and I don’t want to lose time with emails I didn’t want. If I want to stay in touch, trust me, I’ll do it: adding your RSS feed to my reader, connecting on any other social media, subscribing myself to your newsletter… I’m tired of this bad practice, so let’s be clear, if you do this, you’ll lose a customer, a member of your site or even a contact in your network. That’s it!