@benhall I don't see that happening, at least not while these Big Tech servers federate with ANY other servers. MS/Google/any other doesn't want to be held responsible for any platform they can't control. Although it would certainly drive up adoption ... but at that point, they'd likely make their own social platform, which they could have done years ago so they likely aren't interested, etc.
@INTERPUNCT I don’t know. I can see the advantages for them- part of the office suite for example. they can also maintain blocklists of bad domains, like email domains. They are still trying in that space after all- LinkedIn is very much alive, yammer trundles on, Google regularly releases new products etc.