I seem to recall a while back that the shopping channels were made global, so that you didn't have to be in a city to use them, right?
Well I've noticed since 13.0 that although you can turn on the shopping channels outside of town, you can't hear globally or be heard globally, but only by the people in your playfield (confirmed in Lush Fields, Galway Shire and Galway Castle).
While in Galway Shire, for example, I was able to only chat with other people in Galway Shire on the OT Shopping 1-50 channel.
At first, I thought it was so quiet because no one was playing, then when I stepped into Rome, my chat box started scrolling rapidly with dozens of shopping channel messages. When I stepped back into Galway Shire, the shopping spam stopped.