Imagine that you're exhibiting at Macworld Expo and want to hand out CDs containing demo versions of your software. It's easy to create a master disc and a label, and send it out for printing and duplication. But there can be a long lead time for big orders, making it hard to release a new product at the show, and any unused CDs become obsolete quickly afterwards, which is a waste of money and resources.
The clever lads at Rogue Amoeba have come up with a nifty solution to this problem, which they call Live Disc. Essentially, Live Disc is a custom application that presents a Finder-like window to the user, showing icons for demos of Rogue Amoeba's products that you can drag to copy or double-click to launch, just like in the Finder. The magic is that if a newer version of the application is on Rogue Amoeba's server, Live Disc seamlessly downloads that version and copies or launches it instead. If there's no Internet connection, Live Disc simply uses the copy on the CD.
At the moment, Live Disc isn't a product anyone can buy or license, although I imagine that Rogue Amoeba would consider making it one if there's sufficient interest. Far too many CDs are wasted because their contents have become obsolete; with Live Disc and some forethought, nearly any promotional CD could have a significantly longer life span and would be less likely to join the ever-growing waste stream without at least being useful first.