DesktopLinux.com posted an article a few days ago about using a LiveCD as a primary OS, or in other words, never installing. This is something that is increasingly becoming more plausible, as memory prices decrease having a LiveCD load into memory becomes faster in many cases than an installed OS, and as long as you still have some kind of media to write to, you can install apps and save documents without fear of losing them from rebooting.
However, many liveCD distros can be used as a day to day desktop without ever installing them to your hard drive.
Why would you ever want to use a livecd for day to day use, while with about the same effort you can have it running from the hard disk?
LiveCD are great for lots of things. But as soon as you are going to install your own apps and want to save your document, you are using just one computer the same way as a normal linux installation.
As soon as (all/most) computer automagically boot from usb or flash disk it becomes intresting…
If you carry around a USB flash drive with the LiveCD, you could use move from computer to computer, or if you use multiple sessions on a CD like in Puppy, or if you saved programs/changes to a network address (like SLAX) you could move around too. Of course, I agree it will be nice once bootable flash drives take off.
I used to install Linux on the hard disk at every new version of my favorite distro. But I do not see any advantage. Installation or updating take long time, and is specific of a computer. Now I prefer live distros that start fast, and I can enjoy the changes without delay. Some distros, like DamnSmall may easily be customised with extensions, carrying in the CD just the programs I want, as if the Linux was installed, but without the risk to ‘break’ anything. At the end of the session, if I have generated some documents, I save it in my pendrive allowing me to continue my work in another machine. Why I would need to keep installing Linux?