> Or to put it very bluntly: what is this, why should I care, and why not just use the old one?

If you don't mind I'll quote the FAQ[1]:

The previous and current versions of Freenet have several key differences:

Functionality: The previous version was analogous to a decentralized hard drive, while the current version is analogous to a full decentralized computer.

Real-time Interaction: The current version allows users to subscribe to data and be notified immediately if it changes. This is essential for systems like instant messaging or group chat.

Programming Language: Unlike the previous version, which was developed in Java, the current Freenet is implemented in Rust. This allows for better efficiency and integration into a wide variety of platforms (Windows, Mac, Android, MacOS, etc).

Transparency: The current version is a drop-in replacement for the world wide web and is just as easy to use.

Anonymity: While the previous version was designed with a focus on anonymity, the current version does not offer built-in anonymity but allows for a choice of anonymizing systems to be layered on top.

> Which then led to people storing Bad Stuff, and this is somehow addressed in the new version? (I also read some stuff about friends and trust in the previous one, but haven't looked into properly.)

The new version doesn't claim to provide anonymity as part of the platform itself although anonymity systems can be built on top of it. I'd also refer you to this FAQ [2].

[1] https://freenet.org/about/faq/#how-do-the-previous-and-curre...

[2] https://freenet.org/about/faq/#how-does-freenet-handle-harmf...