(with apologies to Pete Seeger for the headline)
It used to be that back in the day, Canadian websites under the .ca umbrella had to be further categorized by a provincial subdomain. For example, the City of Toronto’s website used to be at city.toronto.on.ca, the Toronto Public Library at tpl.toronto.on.ca, and so on.
If I recall correctly, these registration rules (associating the geographic scope of the organization with the domain hierarchy they were allowed to register in) were abandoned in about 1995, at least in Canada. I remember this because my Internet Service Provider at the time was Intranet Technologies of Ottawa, which went from being intranet.on.ca to intranet.ca. (Only later did I reflect on the stupidity of naming an Internet service provider “Intranet”.)
It’s a curious footnote to history, I guess, that most of these province-and-city level sub-domains have fallen by the wayside and most organizations do not use them any more for their canonical website address. However, they reflect a time when the Internet was more rigid and organized according to some sort of taxonomy, and for that, I’m somewhat wistful.