Spreads are the tools of conducting a reading. The manner in which cards are laid out, positioned and interpreted depends upon the structure of the spread.
There are quite a few spreads which are used by Tarot card readers the world over. Yet, spreads are not limiting.
You can even design a spread to answer a particular question for a client, or design one to answer a general situation.
You can find a lot of information about Tarot and related stuff, including several spreads designed by Tarot readers all over the world by visiting the famous Aeclectic Tarot Forum.
Good information.Well written.