I still respectfully disagree. If GitHub really wanted to deceitfully name this feature to foster the cathedral model they would have gone with "branch" instead. In fact, I recall them getting quite a bit of push back for naming it "fork" because it has historically been a pejorative term. Even further, I believe the actual operation is implemented as a branch on their backend for efficiency's sake. So why go so far as to call it a fork?

Well, because you can treat it as a fully maintained source tree itself (and participating like a member in a bazaar). It's easy to turn on issues locally, add collaborators, accept pull requests, and trade commits back and forth between the forks. Now, yes, GitHub does by default "link" it to the upstream repository and it even keeps tabs on how its history differs, but I'd call these features that reflect real use-cases.

Also amusing is how the repositories on kernel.org describe themselves; 149 use the word "fork". Sure, it's probably partly due to how GitHub uses this terminology, but I'd say it's a good thing that forking is no longer pejorative by default — now it's a "hard fork" that's a bad thing.