I find this generally helpful and I like the attitude of these emails, but you are making a massive mistake that every single one of those websites which do the

I find this generally helpful and I like the attitude of these emails, but you are making a massive mistake that every single one of those websites which do the same thing make as well - you don't provide a clear and quick way to be removed from your mailing list. This should be in every email, a simple link or even asking to reply with the word "unsubscribe" in the subject. If you don't do this a lot of people are going to think you're spamming them.