The Source Code Manager (SCM) is Git.
This SCM is the obvious mechanism for meeting the previously mentioned goals.
Not only is it the SCM for kernel.org
but,
Git continues to grow in popularity and supports many different work flows,
front-ends and management techniques.
You can find documentation on Git at http://git-scm.com/documentation. You can also get an introduction to Git as it applies to the Yocto Project in the "Git" section in the Yocto Project Development Manual. These referenced sections overview Git and describe a minimal set of commands that allows you to be functional using Git.