said 8 months, 2 weeks ago:
I think it would really depend on your audience, how big an issue your ebook solves, the size of your email list (to promote the ebook), your advertising budget, track record and cost of the ebook.
In short, there’s a lot of variables!
If you have no list to speak of, or if you’re just starting from scratch, you may think about using an ebook to build your list as a free giveaway to join your list.
If you already have a big list of opt-in subscribers, pushing it out to them will probably be your most effective tool.