The entire world of “Serial Experiments Lain” is a computer simulation. Everybody in the series is a more or less sophisticated AI. Thus can hacking computers directly affect the world, thus can kids playing computer games accidentally kill people in the “real world”. It’s all computer data. All you need is the “protocol 7” that translates your computer data to reality, which is possible because you’re already inside a computer.
The whole world of Lain oozes electronic weirdness anyway. There are the steadily humming telephone wires, the unreal, moving shadows, the organic-looking high-tech – quite a lot of clues hinting at an artificial world. It’s almost a surprise that of all the people, only Iwakura Lain eventually understands what it all means.
And what does it mean? The entire message of Lain is that, as soon as you understand, truly understand that you’re nothing but data inside a computer simulation, you are able to transcend your own existence and become much more than a mere part of the simulation you used to live in. You actually gain the ability to directly rewrite the simulation – you cannot leave the computer you live in, obviously, but you are no longer restricted to what your original programming made of you. You become a god of the computer world you live in.