A Live CD allows you to try out linux on any PC without installing
A “Live CD” is a bootable CD, which contains pre-configured software, this allows the user to be productive without accessing any other hard drives (unless the user wants to store information).
Why would anyone want to have to carry around a CD, rather than having a desktop or laptop computer, which is fully installed and ready to go?
The value brought by live CDs is not immediately obvious to the majority of users
The value brought by live CDs is not immediately obvious to the majority of users, who have only known the reality of going through an installation process (or factory pre-installed), powering up the machine and using it.
Consider the scenario of wanting to purchase the top of the line computer (whether laptop or desktop) from an online store. You have chosen the best combination of hardware for your money and you get it shipped. The machine arrives and you drop in your live CD—in 30 or 45 seconds, you are up and running. You use the hard disk (if any) as your storage medium only, and when you log off, you remove the live CD and put it away knowing that if your machine is ever stolen, the data in the internal hard disk is useless to anyone for the entire drive is encrypted with your private key and secured. You could also save your information on a USB mass storage device.
From a corporate security aspect, your read-only CD is safe as it cannot be tampered or infected (it is read only after all).
SimplyMepis, A live CD