Depends on how you define private. It’s not “private” in the sense that it is accessible to the public interner. It is only more privacy-friendly in the sense that say, unlike Facebook, there is no need to use your IRL ID data, there are no weird algorithms baked in, and no targeted ads. Nothing would keep 3rd-party scrapers from profiling your posts that are public, but at least by default it’s not evil.

… until Meta will arrive on the fediverse…

No one said it’s private. It’s not commercial, there’s a difference.

The data you post isn’t more private like other commenters have mentioned.

On the other hand, lemmy and other open source social media platforms won’t collect behavioural data like other privately owned social networks.

Instagram for instance will track exactly how much time you spend looking at each post to determine your interests and predict which ads you are most likely to click on. Others than that they will also run experiments of changing some features and track your engagement with them.

So in essence, they collect more data on stuff that you don’t explicitly share.

Private? Who told you this was private?

It’s not more private. Who told you it was? What it is is more decentralised and interoperable, and thus more resistant to the bad decisions of individual instances.

It’s not more private. It’s more free. Meaning it’s harder to cut someone’s voice out of the conversation, because the conversation is administered across many different instances.