http://en.wikipedia.org/wiki/Ouija
I find personally,that the Oiuja is a tool,just like any other.It is no less and no more than that.
I 've never experienced any mishap or negativity from it's use and in all honesty,what I can achieve with it I can just as easily achieve without it,using other means.YMMV.
I tend to like my tools to be easy and simple to utilise.Less effort in the preparation,means more effective and active use of my time.
I am afraid I lean very much towards the practise and not so much to the formality of ritual and ceremony.
If I was using my Oiuja,I'd be prepping the room and candles and incense and incants etc And in the 'proper' order and so on....as I 'd do that for any 'entity/higher self/manifestation or contact' type of work....So I don't often work this way.
My Oiuja board sits on my coffee table as a centrepiece.It's a fancy Resin one with glass top and pewter/leaves effect,it was a gift from a dear friend.
Pic below:
It seems that the ideomotor effect and a certain sense of foreboding and superstition increases the chances of having a bad experience,that and the manipulations of those who might find it funny to shake up some friends: re,the internet is littered with "Oh Wow: Ouija is Evil!!!" stories of dabbling.This applies to the first timers and the younger folks mostly,but I've heard of older folks too getting all het up by it,for a party trick gone wrong.
Those who experience the bad first time usually either leave the Occult well alone for ever after,which is probably for the best,for all of us.That,or conversely ,they'll dive in and start to learn seriously after a wee pause for breath.
It is also worth remembering that many Christian fear mongers,on the extreme side, like to exploit the 'Ouija is evil,possessed/terrifying/gateway to Satan tales' as useful propaganda.
Fear controls curious minds quite effectively.
I think any tool can act as a conduit,unconsciously/sub consciously,with enough hyped up energy from the people around it.I 've heard some tales of woe,similar to Ouija ones about dabblers playing with Tarot cards and in one case,the use of a black mirror by friends on shrooms.[That's a garbled one,but a goodie...]
If that sense of expectation and excitement was tuned up positively,then no doubt the experience would be very different.
It is certainly something with a long and notorious Urban legend behind it,so it will no doubt continue to attract speculation and tales of terror,for some time to come.
I do think that if you are using a tool that is said to 'open up portals to other places',it is only sensible to take some precautions re warding and protection.