Oh, story time:

Once I was using Blizzard's downloader to install something (StarCraft, Diablo, I don't remember), and it was kinda slow. I disabled P2P downloads and speed skyrocketed, and I said "Huh, this was unexpected".

When P2P downloads disabled you could see the list of CDNs you're downloading from and mine had a single IP on that list. It looked familiar. Then it dawned on to me. It was the Akamai server which we were hosting in our system room, at 15 minutes of driving distance. After a chuckle, I went to get a cup of tea, because that was entertaining than the game itself.

Then of course, I dived into whatever I was installing that night.

Edit: From the screenshots in the wiki, I remembered that the progress bar was red. It was possibly Diablo 3, then. However, I'm still not 100% sure about it.

I've worked at trading firms where the "reference data master" file is usually a big json or equivalent.

To get the file out to 100s or 1000s of machine they would often use private bittorent to distribute the file out.

Steam has a limited form of p2p delivery, used on LANs: https://help.steampowered.com/en/faqs/view/46BD-6BA8-B012-CE...

Several companies tried this for distributing software.

It was very controversial. Users were angry that software companies were using their internet bandwidth to distribute their software. Made a lot of people angry.