For the news articles themselves, each of the major companies is using a major CMS system, many of them developed in house or licensed from another major media organization.

But for things like journalist microblogging, Mastodon seems like a stand-in replacement for Twitter or Threads or Bluesky, that could theoretically integrate with their existing authentication/identity/account management system that they use to provide logins, email, intranet access, publishing rights on whatever CMS they do have, etc.

Same with universities. Sure, each department might have official webpages, but why not provide faculty and students with the ability to engage on a university-hosted service like Mastodon or Lemmy?

Governments (federal, state, local) could do the same thing with official communications.

It could be like the old days of email, where people got their public facing addresses from their employer or university, and then were able to use that address relatively freely, including for personal use in many instances. In a sense, the domain/instance could show your association with that domain owner (a university or government or newspaper or company), but you were still speaking as yourself when using that service.