[oracuk]

It would seem to me that open standards are the answer to walled gardens rather than 'Free, open source and federated'.

I don't know of any standards-based activity discussing a twitter-like capability but multiple interoperable implementations, open and closed source, free and for money, provides an 'ecosystem'.

I would contrast an ecosystem to a platform. A platform is owned or controlled centrally whereas a successful ecosystem isn't. A well-managed platform ultimately provides the most benefits to the platform owner whereas a successful ecosystem provides the benefits to the most successful entities within it, a playing field to compete within.

[streptomycin]

Well if the standard is open and popular, there will be free open source implementations, and they will be important. And if the standard is open but not federated, it's not very useful.