apt-get upgrade message in sid

[Charles Kroeger <ckrogrr@frankensteinface.com>]

I've been avoiding the removal of my nvidia glx driver with the
workaround of doing apt-get upgrades instead of dist-upgrades.

my sources  /etc/apt/sources.list include experimental along with sid
contrib and non-free sources

When I do the command: apt-get upgrade, after the packages are
retrieved I get the following message:

apt (0.8.11) unstable; urgency=low

  * apt-get install pkg/experimental will now not only switch the
    candidate of package pkg to the version from the release
    experimental but also of all dependencies of pkg if the current
    candidate can't satisfy a versioned dependency.

 -- David Kalnischkies <kalnischkies@gmail.com>  Fri, 03 Dec 2010
 14:09:12 +0100

After hitting the 'q' key this message clears and the the packages
unpack and setup.

What is David Kalnischkies telling me here?

Thanks,

CK