The World Wide Web was born open (every base software was made public domain by CERN).
Then social media developed making it easier to non-technical people to have a part on the internet.
Before Web 2.0 there was television and journals as information sources; Afterwards, people were able to create their own information as well as express their opinions.
The internet started to close at the same rate as ads technology developed. To have a presence online has a cost. When it becomes free to you to have your presence, then you must be the product.
Ad-tech plays a risk to society with its demands for personal information, and it is manipulative by promoting disinformation and extremism.
The centralised social media plays privacy issues and has put the power of moderation in a few big corporations which have been censoring information and pushing to extremes.
The IndieWeb allows diversity, doesn't build any monopoly, and welcomes innovation. Each instance has its own moderation policy and that's the extent of its power.
As with email, you can interact with any server running a free network compatible software. And as with email, that server may have blocked you or not. Your moderation (if you are a system administrator) is limited to your own instance and instances who all have set you as a remote moderation. Every server is a different community who shares a common trust in their administrator and supports him to main the server active. Groups are federated, and therefore, you can interact with the people from other communities regarding common interests.
Please note that how you see a certain group is affected by your instance's moderation. If you happen to be in an instance with a too severe moderation, you may want to leave it or set your own, otherwise you may be getting yourself inside a filter bubble. And that defeats part of the reason why it is worth joining the IndieWeb.
Filter bubbles is when you're only able to see information and opinion that are in conformity with what you believe or reinforce your own beliefs due to algorithms designed to make your experience more personalised. These tend to be used on commercial social media. It's important to note and avoid it. This technology leads to unhealthy extremes because of the absent opposition and debate of ideas.