Sam,
The news was announced on Facebook, Twitter, the home page and our forum. We send emails sparingly but do plan on sending out an email when the "WUS only" subscription is actually available.
Currently, WUS is available only as an add-on to the ZLA coverage. This will change in near, allowing for 3 possible options (ZLA only, WUS only, or ZLA+US). All of these will be available in monthly or annual form.