DVD Duplication and DVD Replication are the two methods you have available to you when copying your precious data. Here are the main differences.
DVD Duplication: This is the process of copying the contents of a DVD or CD to another disc using a DVD drive with write capabilities. Another name for it is burning. You can do this on your own PC using software like Ahead Nero StartSmart. This method is best for burn runs of less than 500. Many companies burn their data using in-house towers, which consist of upto 21 target drives, a hard disk on which to maintain the original source files, and the software to monitor it all. Some towers have a robotic arm that will swap a disc after it has been burnt so that you can leave the whole process unattended. An example of this is the Bravo Disc Publisher. It has a bay that holds 20 discs. It also has a drive for burning and a built in printer and robotic arm to swap and print the labels onto the burnt discs. All this is run by software called PTP Publisher.

DVD Replication: CD and DVD Replication (also referred to as 'pressing' or 'molding') is the original method of manufacturing CD/DVDs. A large CD/DVD molding machine uses raw materials to form a basic CD/DVD. The data or audio is physically stamped on using the glass master. Hence, these discs have a silver look to them. The silver tone is the aluminum that is used to reflect the laser that is used when you play your CD/DVD. Most of this process is automated, the cost per unit becomes factored in and very affordable on orders generally greater than 1000 pieces. DVD Replication is normally used for higher quantities where it's important to get the per disc price as low as possible.

----------