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.
On a cost level, yes it would make sense to leverage mstdn.ca but issue is that CBC wouldn’t have the complete control & the instant brand recognition via hosting their own instance on their domain name.
It’s also much better for the brand to have an account on social.cbc.ca. Something like cbcnews@social.cbc.ca looks better on a branding perspective than cbcnews@mstdn.ca. It’s no different than how organizations use their own domain for emails.