The history of the Ouija board is something that has always been shrouded in mystery. Some people speculate that the board came from Egyptian times and others think that the history is Chinese. There are also some scientists that speculate that the ancient Greeks use divination tools similar to today's Ouija boards.
The Ouija board is a simple board with an alphabet numerical symbols, a movable planchette and is used to communicate with spirits. The etymology of the term Ouija is ambiguous, but it is surmised that the word Ouija is a combination of two words "oui" and "ja", the first being the French translation of yes and the second being a German translation which also means yes. Thus the term Ouija actually means "yes, yes" which is meant to be an invitation for spirits to communicate.
There are number theories pertaining to how Ouija boards work, the most popular being that Ouija boards work as a form of automatism (this being the belief of the skeptic), and the other belief being that the Ouija board is working because an actual spirit is communicating with us. Automatism is believed to be an involuntary act where a person behaves in a certain way without being consciously aware of the behavior. It is believed that they affect the planchette with their hands because of their subconscious mind. When two or more people are using the Ouija board, it is believed that the board is active on the a collective automatism. While collective automatism may account for some successful Ouija board sessions, it is more likely that collective automatism can explain unsuccessful Ouija board sessions even better. If two or more individuals are using the board, each individual has a subconscious that is affecting their body in ways that the consciousness is it unaware of. This being the case, it is possible that two or more individuals will witness a clash of subconscious efforts which makes sessions where weird spellings are incoherent gibberish or nonsensical messages are the result.
For every skeptic who believes in the ideamotor concept, there seems to be another person who believes fully in the power of the Ouija. Most of those who believe stand by the idea that spirits that you can contact through the Ouija board come from the "lower astral plane," and are often confused or violent. They tout the importance of never asking a spirit to come into the physical plane, nor count numbers or the letters backward on the Ouija board. Most of these types of people simply say "stay away" as a way of staying safe when it comes to a Ouija Board.
Either way you believe, Ouija boards have a certain place in our history, our folklore and our legend. They've evolved through history (though not by much, and if you don't believe me, check out this gallery of vintage Ouija boards throughout history)