It's often easy to overlook a simple reminder about what your product does when sending out a newsletter to your users. Especially when you've not been frequently keeping in touch with them.
Also, if you use a 'no-reply' email, it's just adding insult to the injury.
And it comes from a no-reply@. That's just spelling "f*** off" to me.
It goes to show how much you want to hear from your users. Just because big companies does it, doesn't mean you should.
That reminds me of silly 'terms & conditions' appended at the end of your email signature. Well, let's not go there.