Truly successful applications based on decentralized networks?

The internet? And many of its protocols that came with it, including email, etc.

Sidenote, and I dunno if it's what you're implying but many people do: "company x takes decentralized solution, offers services on top that aren't decentralized" doesn't make the whole thing centralized. Git is still a wonderful decentralized tool. There is very little functionality that Github offers on top of git that is particularly centralized -- permissions, maybe, but that's about it and it doesn't make much sense to centralize them. Nearly all of Github's featureset could be, like, a separate app that has nothing to do with git - it competes with the atlassian suite, for example; they just chose to make the projects "repo-centric" and make git a first-class citizen. They've also supported svn for a while.

Skype used to use each user's PC as a node, and every once in a while your PC would become a "supernode" and handle other people's traffic. The only part that was centralized was the login, as there was only one global namespace. [1] It was end-to-end encrypted too, tho it was proprietary and maybe backdoor'd but what's new. After microsoft bought it they started handling the supernode traffic. "nine months after Microsoft bought Skype, the NSA boasted that a new capability had tripled the amount of Skype video calls being collected through Prism" [2]

[1] "An Analysis of the Skype Peer-to-Peer Internet Telephony Protocol" http://www1.cs.columbia.edu/~salman/publications/skype1_4.pd...

[2] https://www.theguardian.com/world/2013/jul/11/microsoft-nsa-...

So... web browsers?

I think it's important to distinguish between applications and protocols.

Successful applications based on decentralized networks seem to be a mix of both application code and protocol. So in discussing email, we are probably discussing SMTP and IMAP, and then the applications are the email clients that speak those protocols. Similarly, when we talk about the web we are talking about TCP/IP and HTTP(S), (also DNS, CGI, etc) and the browsers are again the clients that speak those protocols.

It seems to me that the success of the world wide web has entirely to do with TBL making sure that his superiors released his work into the public domain[1].

Whereas with something like World of Warcraft, there you have an extremely successful application, but it's based on a proprietary protocol, proprietary code, and centralized networks. Could it have been more successful if Blizzard had released the protocol and client into the public domain?

[1]http://cds.cern.ch/record/1164399

Freenet has been around since 2000, and I remember wondering why Wikipedia was always begging for millions of dollars when there was a way to have users host the content. Sure you don't want to ask someone to install a node just to view wikipedia, but there's enough editors and archivists out there that would be willing to be mirrors if it was just a background process you could run like freenet. It got me interested in programming and I learned that handling conflicts on a decentralized system makes things difficult, plus apparently there's more to running an encyclopedia than hosting servers.

Now wikipedia is mirror'd on IPFS, but its just a mirror, you can't edit. Still the performance of it is surprisingly good.

https://ipfs.io/ipfs/QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1m...

Email remains underrated in terms of decentralized notions.

Finger? https://finger.farm

The early days of the web, before governments and ISP's stepped in (for arguebly good reasons).

https://en.wikipedia.org/wiki/World_Wide_Web

DNS, SMTP, finger, git, HTTP, Napster, ssh, Torrents, eBGP I guess.

https://Arweave.org is promising

Bittorrent ¯\_(ツ)_/¯

IPFS

emule, usenet

there's very little massive potential.