[eggnet]

There is always a second filter bubble. In the case of non-federated sites, that filter is in the form of the policy of the site and also the algorithms used to sort feeds and replies.

With federated solutions, users have a choice.

[cubefox]

They have a choice? Is it transparent for average users what is withheld from them and where? And where their own posts are withheld? If no, they don't really have a choice. If such a choice even exists.

Twitter is fairly lightly moderated I think, and the "following" tab gives a raw timeline.

[eggnet]

Average users will leave toxic environments, and be attracted toward content that is compelling to them.

If federated services pick up steam, they will pick between a few popular options.