Content quality alone does not determine how fast a newsletter grows. A lot depends on where the newsletter is being promoted and how easy it is for new people to find it. A newsletter with average content but strong promotion through social media, partnerships, or referrals will grow much faster than a great newsletter that nobody knows exists. Subject lines also matter a lot because they decide whether someone opens the email at all. People will not read what they do not open. So in your opinion, does promotion matter more than content when it comes to growing a newsletter?