If you have a piece of gold, and I want it, I must deprive you of it so that I might have it. With information, I can copy it from you, you still have it, yet I can benefit from it too. Even in these simple terms, it is clear that information is different from what we conventionally view as property. Freenet drives this fact home to people, and so I hope it will be useful for making this point. Two words - digital signatures.
Someone can indicate that a file can be trusted by applying their digital signature to it.
This way, someone could build up a reputation for being trustworthy, while remaining anonymous - I think this is the best way to address the issue of trust on systems like Freenet.