If you would ask this question, “Which one is more important – the mailing list or the product?” any savvy marketer would answer you, “The mailing list”.
Principally, any wise business person puts the importance of hungry demand (and not just any demand) in front of the product. In other words, there is no product if there is no demand! And a mailing list represents the demand or your business if you would like to call it.
If you frequent the Joint Venture forums and membership sites of any kind, you will find that product and service owners need mailing list owners more than the other way round. This is because the mailing list owners have the prospects that the other type of partner is looking for to sell to.
And if you are a mailing list owner, you do not have to necessarily make money from selling your own product. You can sell advertising space or craft a Joint Venture with product owners in return of commissions, recurring or not.
Most of the biggest success web businesses on the Internet today often establish the mailing list (or subscribers) first, before the product.