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.

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

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 your data. If you’re not comfortable with any instance then you should look into hosting your own!

This is my understanding without doing any research on Lemmy specifically and what, if any, differences there is compared to others.

does admin has access all of our data?

Always assume that the answer is Yes. Regardless what you are using within the fediverse.

can he sell the data to some big corporation?

Again, Yes. Buti think they would be breaking their own privacy policy:

Looking at https://lemmy.world/legal and it refers to https://mastodon.world/about where general rules are clearly laid out that is also enforced afaik on lemmy.world. Them linking that page makes me assume that the same privacy policy that is used on mastodon.world also applies here, this can be seen at https://mastodon.world/privacy-policy

Do we disclose any information to outside parties?

We do not sell, trade, or otherwise transfer to outside parties your personally identifiable information. This does not include trusted third parties who assist us in operating our site, conducting our business, or servicing you, so long as those parties agree to keep this information confidential. We may also release your information when we believe release is appropriate to comply with the law, enforce our site policies, or protect ours or others rights, property, or safety.

Your public content may be downloaded by other servers in the network. Your public and followers-only posts are delivered to the servers where your followers reside, and direct messages are delivered to the servers of the recipients, in so far as those followers or recipients reside on a different server than this.

To be clear, the admins do not need to sell the information you share publicly, afaik it’s already freely and available in the open to anyone (as mentioned above in the privacy policy) and there is nothing stopping any outside party from scraping this data.

They do need to update https://lemmy.world/legal though asap to make things clear.

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.

This is a concern regardless of instance and the size of the instance. At least in my mind.

Personally I don’t have too much concern right now but if anything happens that changes that then I’ll just leave.

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.