As it says in the title, the BBC is starting its own Mastodon instance. I think the CBC (and other news networks) should do similar. Particularly with the recent passing of Bill C-18 it seems like a world where the links we share are crossposts to news organization’s own content is the perfect resolution to that whole issue.
Also, you might want to take a look at https://zdf.social/@ZDF and https://ard.social/
ZDF and ARD are the two biggest broadcasters in Germany, and they both have their own ActivityPub (Mastodon) server.
In case you needed some extra convincing that other large mainstream news organisations also have realised that this is actually a good idea that makes sense ;)
A big news org from France is also on Mastodon with like 50k followers, but I cannot remember the name right now
The actual Dutch government now also run their own instance.