The answer is always yes for hosted services. The data has to be stored somewhere, and it is readable if not explicitly encrypted on your device before being send to the server. Some things like passwords are usually handled differently though, they are not readable by anyone.

That's one of the reasons why picking an instance is a big deal. You trust that instance with moderation and handling of your data. If you're not comfortable with any instance then you should look into hosting your own!

That begs the question, does admin has access all of our data?

Yes, of course.. The data is on his server, he has access to his own server and everything that's on it. This is true for any online service whatsoever, the only exception would be encrypted data.

If he wants, can he sell the data to some big corporation?

Not legally, unless the privacy policy is changed.

I’m not too worried about it, because:

• He’s been running a fairly large Mastodon instance too, and it seems like it’s been going well.

• If I end up disappointed, the beauty of the fediverse is that I can up and leave. In fact, I already did: I started with an account on Beehaw, and I moved to Lemmy.world when they defederated a few instances whose contents I was interested in. It was a fairly painless move.

So for now I’m donating $5/month, and we’ll see what happens from here.

Here are the key factors I see behind Lemmy.world’s success:

• Lemmy.ml was buckling under load, and at least one of the admins (and Lemmy developer) is an unapologetic communist & China sympathizer.
• Beehaw.org is a classic powermod situation where the admins want to micromanage every community. It also was struggling under load.
• Lemmy.world was scaled quickly to handle the load, hasn’t been controversial in their policies, and for the most part just works.

As has been pointed out in other comments, the power of the fediverse is that if one instance becomes “evil”, users and communities can and will abandon it for another instance.

Here are the key factors I see behind Lemmy.world’s success:

• Lemmy.ml was buckling under load, and at least one of the admins (and Lemmy developer) is an unapologetic communist & China sympathizer.
• Beehaw.org is a classic powermod situation where the admins want to micromanage every community. It also was struggling under load.
• Lemmy.world was scaled quickly to handle the load, hasn’t been controversial in their policies, and for the most part just works.

As has been pointed out in other comments, the power of the fediverse is that if one instance becomes “evil”, users and communities can and will abandon it for another instance.

Isn't it a bit funny that you are asking that after you have already joined the server and accepted all the rules, etc?

Do we know he’s a jolly good fellow?

I mean that's up to you to decide, idk. what answer you are expecting.. You have the same information on him as we do, the info on his mastadon:

https://mastodon.world/@ruud

It will be the case with the fediverse in general. But the point of the federation is to make it easier to switch instance, reducing the power of the owners.

An ideal solution to this would be a fully distributed system. But this has many technical challenges as it pushes the complexity on the client side. And the moderation is then also more complex. Federation aims at finding the good trade-off between giving power to a few capable people to manage the network, yet making it difficult for them to abuse the system as users can easily switch ship without losing their entire social network. This is similar to emails - changing your email address is a pain, but you don't lose your contacts and can still talk to people with your new address.

I mean, every website except one you run on your own hardware has this exact problem: whoever is running it owns it completely, and they set the rules (within legal boundaries).

The only ways you can avoid this are:

1. Run your websites yourself (which is kinda low-value; imagine the Geocities era, but everyone has to set up the hardware and the networks and the domain names and everything themselves), or....
2. Stick to websites that have an easy "escape hatch", where you can easily bail at any time. This is how Lemmy/Mastodon/Kbin and the Fediverse at large are designed: if your local server admin sucks, well, you can just join a different server, and you can still see content from all the other servers as before (assuming the place you "escaped" to hasn't blocked them).