[1] "branch-review model", as in, a model where a review is about a topic-branch, whether it contains 1 commit, or many. Or even a branch from a fork. In other words the pull-request model from GitHub. And yes, on GitHub one can also create a pull-request from one branch to another, within the same repository (e.g. mediawiki-core/feature-x -> mediawiki-core/master or mediawiki-core/feature-x-y-z -> mediawiki-core/feature-x) .
[2] http://zachholman.com/talk/how-github-uses-github-to-build-github
Oh, I didn't know that pull requests could be used without forks. So, yes pull requests provide branch reviews and the added benefit is that non-coders can get involved in the discussion as well and keeps everything in one place, if you are looking at UI design, for ex.
Subbu.