Most of the things we use daily fall into one of two categories: ownership or rental. While both models come with their advantages and disadvantages, many lean towards ownership as it tends to be more clear what can be expected from such a transaction. With rental, you never truly own what you are renting, and as such, the terms can always be changed by the company. In an example of having the worst of both worlds, computer software you own can still often need to "phone home" and be activated on a server to work. The problem with requiring a server for your program to run is that you are at the mercy of the owner of the server for things to always work. This is exactly where users of Adobe's Creative Suite 2, 3, and 4 find themselves, as Adobe has said the activation servers for those particular versions had to be retired. This means users will no longer be able to use a piece of software they originally paid for if they ever have to reinstall it.