What the Gates Foundation donated to Libraries (at least here in Louisiana) was hardware (servers, workstations, networking equipment, etc, with the software installed).
Libraries could have changed the software (with, of course, loss of support) at any time in the project. Our site, <A HREF="http://library.beau.org/" TITLE="beau.org">Beauregard Parish (Public) Library</a beau.org> agreed to be a regional training lab (got more computers that way) so we agreed to run them pretty much as issued for awhile so that the Gates Foundation could use them for training.
At the end of the period agreed on for training, we were free to convert them to Linux. We deeply appreciate the hardware that the Gates Foundation made available to us even if we do consider that particular group of pc's to be 'the reborn'<nobr> <wbr></nobr>:-)
Initally we installed RedHat Linux. They are now being upgraded to John Morris' <A HREF="http://whiteboxlinux.org/" TITLE="whiteboxlinux.org">WhiteBox Enterprise Linux</a whiteboxlinux.org>
High on our list of pluses is that we can allow our patrons to do lots of things like download and chat without fear because an application John put together for us allows us to restore the computers from image - this is done automatically on a timer or can be run on an individual computer when the need arises.