The Eurovision Song Contest is organized by the European Broadcasting Union (EBU) an organization set up to regulate TV tech. In short they exist to make sure a TV bought in Spain also works in Sweden. As such the EBU also grants full membership to countries that are not part of Europe but have strong economic ties with the continent and therefore are part of the European Broadcasting Area. That’s how we got Israel in the contest. Australia also competes because (a) they are an associate member (b) they have an long history of airing the contest even before they competed © they spend a large sum of money every year to make the EBU forget where exactly Australia is located.

The US doesn’t participate but a couple of years ago NBC bought the rights and tried to mount an “American Song Contest”. It didn’t work all that well because it was hamstrung by the rigid structure of American network TV. The ESC works (in part) because it is three nights only and they tried to make an entire season of television.

The other one did as well (https://zdf.social)

And thanks to activityPub there is interoperability between services. I only have a Mastodon account, but I can follow people on pixelfed without problem. It moves the focus back onto communicating rather than being on the platform

Kind of both. You get to decide who you federate with but deciding who ferdarates with you is opt out. By default your server doesn’t know any other server. But you can search for communities on other instances by taking the url of the community on the other instance and entering it into the search field. This way the other server gets indexed by your server and after that federation is automatic

E-Mail is a federated standard, so in that sense every mail provider is part of the fediverse.

I think you are confusing fediverse with non profit and/or open source

If that is your question than yes there are alternatives out there. For example murena, the organisation behind the degoogled android fork /e (more information)