Look...If you want, listen to the people who will tell you it's just a harmless game. it can be, just so long as that's what you believe it to be. Un-belief can be a great defense against the paranormal. It can also be a very dangerous one, since, if your not-believing slips even just a little bit, your defense goes away, and then where are you?
These kinds of spirit things (Ouija, auto-writing) can be dangerous to people if they don't know how to defend themselves, remember, "if you call, something will answer, what it *is* isn't important, something will answer".
It really doesn't matter if it's a "real" spirit, just a figment of your imagination, chunk of your subconscious, or even a "demon". You are giving it power, and letting it have control. If you don't know how to keep *you* in control, it's a situation that could get out of hand real fast. That's when the "I don't believe it crowd" usually starts believing, and then their fragile defense goes out the window.
The best way to look at it is this, if you need to ask these kinds of questions about using the board, then you probably aren't ready to deal with things if they go wrong. Not everytime one of these things are used does something get contacted, or things even begin to heat up, it's when something really responds that things can get out of hand, and then you really need to know what to do, and the confidence to make it work.
Defend your mind, it's the only thing you've got...