You're viewing the documentation for the experimental version of Vagrant (the 1.x series). The current stable series is 1.0.x and the documentation can be found here. You can learn more about the Vagrant versioning scheme here.
This part of the site documents Vagrant from top-to-bottom, including all the details of every feature that Vagrant exposes. If you’re just getting started with Vagrant, it is highly recommended that you first read the getting started guide.
If anything is unclear in these docs, please let us know by filing an issue or contacting us for support.