When drawn on paper, this is a 2D representation of the three dimensions. For example, when you draw a cube on a sheet of paper, this is still 2D, but it is a 3D representation, unlike a drawing of a square. 3D movies are labeled as 3 dimensional, but they are really just a 3D representation of a 2D object.
In July 2010, CentOS overtook Debian to become the most popular Linux distribution for web servers, with almost 30% of all Linux web servers using it. Debian retook the lead in January 2012.
For official instructions on how to use Debian Backports, visit http://backports.debian.org/Instructions/ . If you want to create a non-official backport of a package you need, have a look at SimpleBackportCreation.ebianReleases. You are running Debian stable because you prefer the stable Debian tree. It runs great, there is just one problem: The software is a little bit outdated compared to other distributions.