It's not really that new, it's just the term "pull request" that's new. I've worked in several projects where prior to committing code change, it was shared out

It's not really that new, it's just the term "pull request" that's new. I've worked in several projects where prior to committing code change, it was shared out to the team in form of a patch, feedback gathered, and only when everybody was happy with it, it got committed. Or, a bit dirtier solution - a commit was made with an explicit request for a closer review from the rest of the team.