Thoughts from Vancouver Island
I absolutely agree with the intent of the area code format. But I don't think area codes are specific enough to achieve the objective of clustering topics relevant to viewers in their area. Area codes, as they currently exist are not specific enough. Rather than being exclusive, they are too inclusive.
For example: in BC the 250 area code applies to Vancover Island plus most of the rest of the province that isn't considered "Lower Mainland".
Distance, time, and costs (ferries) preclude most V.Is.folk from whipping up to Penticton, Kelowna, or Kamloops to take in an afternoon show & shine or a cruise-in. So because of time, distance, and costs, gearheads are most likely to search out events in their geographical region. I'm thinking that under the provincial heading, OP's could flag their announcements with their regional identity. Eg: if posting an announcement for BC viewers, include (in bold to catch their attention) the sub-heading of Lower Mainland, Vancouver Island, Sunshine Coast, Southern Interior, or Northern Interior.
I realize my suggestion may not be the best way to achieve the objective; but it's one way. Let's hear from other CCF members. What other ways can you think of to "skin this cat"? :seeya: