> I think GitHub added the “pull request” as a really useful add on to git and that really made it take off.
For the sake of correctness, the concept of pull requests was not introduced by Github. It already existed in git in the form of the 'request-pull' subcommand. The fundamental workflow is the same. You send the project maintainer a message requesting a pull of your changes from your own online clone repo. The difference is that the message was in the form of an email. Code reviews could be conducted using mails/mailing lists too.
This is not the same as sending patches by email. But considering how people hate emails, I can see why it didn't catch on. However, Torvalds considered this implementation to be superior to Github's and once complained about the latter on Github itself [1].
[1] https://github.com/torvalds/linux/pull/17#issuecomment-56546...