I grew up in Cambridge Ontario, we had community mailboxes there since the 80s. It wasn't until I moved to Toronto in my 20s that I discovered Canada Post does door to door mail delivery.

I mean there was no need to notify anyone. you just checked the mailbox every day. If you had a package there was a key in your regular mailbox that would open the larger boxes at the bottom. then you'd just throw the key in the mailslot at the top of the community mailbox.

I always assumed this was a thing.