Another possibility is making echo chambers explicit.
A feature called "bubble". When you go to the "bubble" you only see content from the tags and people you actively follow but with a sidebar of "what's going on in the rest of website".
Bubbles could only be activated for people who have contributed a certain amount of posts and/or comments, like a powerup.
By default the website is like it is now, instead of having the ignored list activated, the drawback is that people might only use such bubbles and never go back to the rest of the website.
I still haven't thought about an incentive to leave the bubble if activated.
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