For
USB Flash drives, also known as
pen, thumb, or keychain drives, how you remove them depends on the
Operating System you are using.
For Windows 98/XP you should always click on the Start Bar icon for Removeable Drives

to Safely remove the drive.
For mechanical removeable media like Floppy, Zip, or CD/DVD Recordable disks, you should always wait until the file(s) on the disk are no longer in use
Generally, a file is in use when it is opened by some Application such as Microsoft Word or in the case of recordable media, Roxio CD or DVD Creator Deluxe
Removing media from the PC while the file(s) is/are still open will often result in corrupted files, and sometimes the entire media will be corrupted.
The above rules for files in use applies as well to Flash drives, and pulling out the drive without properly disconnecting it from the Operating System can lead to corrupted files, or even worse, a dead Flash drive.
If you are using Mac OS X you can simply drag the Flash drive to the Eject icon on your Dock.
