Burning a CD or DVD is great for backing up stuff, transferring stuff to another computer (even a Windows PC), mailing to somebody, or offloading (archiving) older files to free up hard drive space. You can buy blank CDs and DVDs incredibly cheaply in bulk—$20 for 100 CDs, for example—via the Web.
You can burn a disc in either of two ways: with the blank disc inserted or without.
The burn folder is a special folder that you fill up by dragging file and folder icons to it. Then, when you’re ready to burn, you just insert the blank disc and go.
The burn-folder concept has a lot going for it:
No wasted hard drive space. When you use a burn folder, you’re not using up any additional disk space as you load up a disc with files and folders. Instead, the Mac just sets aside aliases of the files and folders you want to burn. Aliases take up negligible hard drive space. When you finally burn the disc, the designated material is copied directly onto the CD or DVD.