“The Debian project is pleased to announce the fourth update of its stable distribution Debian GNU/Linux 4.0 (codename etch). In addition to correcting several security problems and a few serious defects in the stable release, for the first time in Debian’s history an update for a stable distribution also adds support for newer hardware by giving users the option to install newer drivers. …
“Etch and a half” is Debian’s desire to support hardware that requires updated drivers. This marks the first time the Debian project updates several core packages in its stable distribution without security implications and demonstrates its huge dedication for their users.
Components newer than the first release of Debian GNU/Linux 4.0 (“etch”) that were not supported yet will be detected by an updated installation routine which is able to install a newer Linux kernel (2.6.24) on the freshly installed system. This revision includes packages that are based upon the Linux 2.6.24 kernel as well. Installation of these additional packages is not required and will not occur by default. The existing 2.6.18-based kernel will continue to be the default kernel for the etch release.”
Release Announcement: http://www.debian.org/News/2008/20080726
This means that for the first time in Debian’s history we see a new kernel release (2.6.24-etchnhalf.1) besides the kernel that initially shipped with etch (2.6.18) in the effort to support new hardware that requires updated drivers from 2.6.18. Even though there were several solutions for this already from using backports.org kernels, to building your own kernels this is a nice addition, especially for the installer but also for people that don’t like to use packages outside the stable repositories.