The Ouija Board was first introduced in 1890, from which it was not associated with the idea of paranormal contact until popularized by a spiritual leader during WWI.
To use a Ouija Board, the user(s) put their hands on the pointer, and ask a question. The pointer will then move around the board to spell out an answer, or depending on the question, will move to 'Yes', 'No', 'Sun', 'Moon, or 'Goodbye'.
Although most users will blame the movement of the pointer on a paranormal being, there is a scientific explanation for this phenomenon known as the Ideomotor Phenomenon.
The Ideomotor Phenomenon is when a person makes an unconscious movement, based off of a strong conscious decision or emotion. This is also the same when the body reacts to pain, and when the body cries in response to a strong emotion.
However, even with this explanation, strange events involving the use of the Ouija Board, events which although can most probably be explained by scientific fact, have a strong negative effect.
There have been a notable number of complaints and talk of the dangers of the Ouija Board by users. Most who have had a bad experience with it have talked about the feeling of a 'presence', usually one with dark intentions. Some have cut straight to saying that they are possessed, and that they are constantly be followed and/or watched.
Many occult and religious leaders have spoken out against the use of Ouija Boards, saying that they are dangerous and should be used by no one. A popular spiritualist, Edgar Cayce, also has said that the Ouija Board should not be used, least be those who are not practiced with the act of contacting spirits.
A common belief and/or explanation as to why only certain people have had bad experiences with the Ouija Board, is that certain spirits, whether they be bad or good, can 'latch on' to those will weaker will power, or those who are easily frightened or spooked.
NOTE: On a personal and religious note, which can be taken as you will, there is another 'fact' about the Ouija Board and contacting spirits in general, which will only relate to you depending on your belief.
In the Bible, it is said in a notable amount of places that man is not able to contact the dead, as the dead are no longer there. Having said this, the Bible doesn't say that it isn't possible to contact... other entities.
1 John 4:1 states:
'Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world.'
Although this verse explains that there are both good (Godly) spirits and bad (Demon) spirits, since this is also completely based on the belief's of the Bible, it is also wise to note that the Bible talks about refraining from the act of trying to contact the dead.
Simply, according to the Bible, if you are using a Ouija board, any 'spirit' you contact, if you do in fact contact one, regardless of what they may say, is an evil entity in disguise.
Remember, this note is purely a personal and religious idea, one that I felt needed to be noted, and is simply another idea/belief.