federation is just one way to achieve some form of decentralization... but only on one axis. the axis of "service provider choice". what is needed alongside this is a great "unbundling" of services.

in the usa, if you want to sign up for just internet, companies often (more often in the past) force you to bundle in phone and tv service as well. we can think of one of fedi's current problems as the bundling of several services into a single provider -- identity, data, communication.

another aspect of federation is that it inherently requires giving up control. once your information crosses the threshold or boundary, it is outside of your control. so, how much of your information do you want to cross the boundary? maybe you're okay with providing your identification, but do you really want to provide your data too? what do you think other systems will do with that information?

with federated identity, you can get past gatekeepers and enter some venue. but the data stays in.

actually, taking data out of such a system is known as "exfiltration".

if you imagine a website as a venue, and your personal website as your home, and let's say a forum is your local community center.

federated data in this sense is like corresponding with people at the community center, in the comfort of your own home, via sending them a letter in the mail.

not federating that data would be like instead inviting people from the community center to come visit you at your house.

once the letter leaves your house, that copy of information is no longer "yours".

with data being split like this depending on the site, you have some possible approaches for participating in a discussion at your local forum or community center:

1) the forum owns the data. you auth into your local actor there.

2) you own the data. the forum is merely an aggregator that links to it.

3) the data owns itself. both you and the forum link to it.