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.
The BBC instance is trying to fulfill a different role than mstdn.ca fulfills. The social.bbc site (and presumably a similar CBC effort also) is not open to general membership, strictly BBC employees and content. So conceivably a CBC journalist could have a social.cbc.ca account for their work and a mstdn.ca account for their personal life.