TLDR: i2p is a gate to a different, on paper completely separate, network that runs on top of the internet (an overlay network). Think of this kinda like onion websites in Tor. They exist in a parallel reality.
ipredia was apparently an OS build geared towards i2p. What I meant is a properly configured Virtual machine that would make it impossible for stray network requests to escape the i2p space etc. Of course your host computer must be encrypted (system partition too) for sufficient security anyway (if someone had your PC and wanted to convict you for just anything - they will find something they can use just to hurt you. Even if its just "a leak" to "journalists"). You aren't required to turn over passwords unlike in the greatest of all the UK.
Please note someone said that for your local node to be well integrated into the i2p network it should be online for at least 24h. It's probably best to have something like Raspberry Pi running for this purpose (that thing can also be made into your own backup space/cloud at home. no need to trust some company with your data). There're plenty tutorials out there for anything, only takes some time and will.
(post is archived)