Comment 61 for bug 342671

You may look at this page: http://packagekit.org/pk-intro.html
Basically, PackageKit allows applications to interact with the package
manager without knowing exactly what it is (yum, apt, zypper etc.).
It basically provides those advantages:
 * Boot time security updates
 * Installing files automatically, e.g. openoffice-clipart
 * Installing new features, e.g. smart-card readers
 * Allowing unprivileged users to install software in a corporate build
 * Opening unknown file formats
 * Removing dependencies for files
It also has a lot of other benefits, check our Richard Hughes summary on
the pkit website.