They're invalid because there aren't organizations with those names, not because they somehow all chose hydro.ca. instead.
I agree, however, that 3-level domains are hugely on the decline in Canada... and I'm quite sad about that.
Good! Those provincial subdomains of .ca (resulting in 3rd level domains) have gone into almost total disuse in Canada. Even exceptions like hydro.mb.ca, where each province could
legitimately want to do the same thing, is not being used much anymore. I just spot-checked hydro.on.ca and hydro.ns.ca, and they are invalid.
Hartmut
We have decommissioned
muug.mb.ca for incoming email as of today. If you
have aliases/contacts/whatever set to use that domain for email, please
muug.mb.ca will continue to work for other purposes, such as web access.
We are disabling email to it to reduce incoming spam.
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