Theory #1: The mere act of publishing content on a regular basis does a lot of the "distribution" work for you -- if you consider search engines a distribution channel. (Which I do, considering how often people use them to find content.) If you create content on a regular basis that's informed by keyword research and optimized for search, Google takes care of the rest of your content distribution plan.
When you are launching a product and want to attract potential clients, it would be wise to mention in the letter how this product can help the clients and their customers. Mention the benefits of the product and tell them how unique it is. In the end, you can mention that they can buy the product from a certain location or a specific location, which you want to mention.