Beyond the fact that many Windows XP installations are hardware-bound, no doubt there are users who are application-bound as well. While Linux has no shortage of applications, there could be any number of legacy or custom apps that simply don't exist in Linux. For those use cases, a Linux installation or LiveCD approach might prove to be more troublesome. Linux does at least include some Windows-type capabilities by way of the Wine open-source application that can enable some (but not all) Windows apps to run on Linux.
For larger installations and those with the resources to invest in new hardware, it is also likely possible to virtualize a Windows XP installation within a virtual machine running on a Linux host. While the core XP operating system might not be getting any additional security updates from Microsoft, within a Linux virtual machine a specific application has the potential to be isolated and secured through policies that limit risk.
Unfortunately, while Linux does represent a lifeline for Windows XP users, I suspect it will be one that is not taken. The simple reality is that many of those users who are still with Windows XP simply just don't know enough to care. Yes, I know there are lots of XP machines running cash machines that banks do care about, but there are also many machines sitting in libraries, schools and homes around the world where people simply don't know any better.
The challenge for Linux is the same as it always has been. Linux desktop vendors need to more aggressively push the message of Linux as widely as is necessary. Linux can provide a freely available, safe option for Windows XP users, but only if the choice is clearly explained and promoted.
The end of Windows XP could well represent a golden opportunity for Linux, as it represents a lifeline for old hardware that is still useful for computing, even if it's not useful for Microsoft's operating systems.
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.