If you want to distribute a file, you could just put it up for download in on your web server. From there, you would just distribute a url that would look pretty much like this:
You could also do that in a different way. Instead of putting a file up for download, you could let users download a file in which you indicate a rendez-vous point:
You would just be an index service. Users who want a copy of the file (peers) and users who already have a copy of the file (seeders) would register with the rendez-vous service, also called the “tracker”. From there on the service would disclose to the peers where to find a copy the file with which seeders:
This is a simplification of how bittorrent works.
Is it an efficient way to distribute a file? It is only efficient, if the index service wants to claim that he does not distribute the file. The tracker service can also claim that they do not distribute the file. The file is being distributed by anonymous seeders. This is only an efficient way of distributing a file if it is illegal to do so.
Now, the strategy only works partially. They still put Gottfrid Svartholm (The Pirate Bay) in prison for assisting to distribute copyrighted files. The court admitted that, technically, he never distributed any copyrighted file, but they still put in him jail for facilitating the process. He disclosed to the users where they could find rendez-vous points to distribute these files amongst each other. What the court achieved is not that index services have disappeared but that anybody running one prefers to stay anonymous.
How would you keep and update a financial ledger, if you feared that someone would try to take control of it or try to shut it down? So, indeed you would seek to distribute copies across thousands of computers around the world. How would you update such a ledger? Let the computers who hold a copy, play a game. The one who wins the game, is allowed to update the ledger, called the “blockchain”. Now we have a system over which the courts have no control. It is distributed across the 200+ jurisdictions of the globe. No court order can reach even a small fraction of the system. Nobody can impose his will onto that collective. Goal achieved.
New swarmification protocols — turning things into swarms — regularly spring up. Swarmification is meant to create a whack-a-mole situation. The tor network is another example. The one thing that they all have in common, is that they seek — and largely manage — to prevent governments from controlling them. It is an arms race in which swarmification keeps evolving and stays one step ahead of government regulation.
What could a bank or a stock exchange, such as Nasdaq, possibly be seeking in the concept of a blockchain? A bank or a stock exchange are always under full control of government, regulators, and courts. A bank could impossibly be seeking to achieve the same goal of freedom from control as bitcoin. If it made sense for a bank to implement a blockchain, it could also make sense for them to reuse the bittorrent protocol for something? I do not see how, but some people seem convinced that they can make the blockchain work for banks.