Also if someone would to put this on a CD for a gift, it would have to have a modified installer on it, and all the basic blockland files that never change. (Default texture files, ex.) the installer would only install the add-on and saves and folder that do change on the hard drive. Then it would have to play a modified blockland that takes the default files from the disc, and the non- default folders (like add-ons) from the hard drive. Because If it was just a regular blockland installer, you wouldn't need the disc/ the folders would be on the disc and if you don't have a disc drive that comes with a burner you would be screwed.
It would probaly also come with something that would connect with steam, like how you can buy a game in a store, and it would be in your steam library.
It would also have to come with a piece of paper with a blockland key on it, and an instruction manual.
... Wow I like going in depth to things.