In a lot of respects, the internet is like brain cells connected by synapses. Each cell (computer) is independent on its own, but when connected by synapses it provides the ability to communicate with all of the the other cells (computers).

The protocol for moving packets of data around has been agreed upon by all.

So, I send a request for data, and the request gets passed around until it reaches its destination. The destination retrieves the requested data and sends it back to me in little packets, which get reassembled and put on my computer screen for me to read.

The internet is just the delivery and retrieval system. It's pretty dumb, all in all.

What's important is what is happening at each brain cell (computer). Is it performing a useful function (legitimate business) or is it doing something nefarious (voter fraud, human trafficking, etc.)?

If someone has taken control of the delivery system and can access the data on individual computers, well, that's a lot of power. In theory, one could control the flow of information. Of course, the data isn't just sitting out there unprotected. There are lots of mechanisms in place to protect the data, but that's not to say it can't be hacked into. For every lock, there is a key. For every front door, there's a back door.

Lots of possibilities for what a group of intelligent people could potentially do, especially given that the internet is basically modular. Pull out one piece and replace it with another piece.

Could you control the flow of data? Could you replace/manipulate the data? Could you control what data is viewed and what is not? Sure, why not? There isn't a piece of code in the world that doesn't have a bug or two or three in it. It would just be a question of taking advantage of the situation at hand.