Nah, I can't say I’m convinced at all. For starters, it was first released as a novelty game, in 1890. You can buy the thing in "Toys 'R' Us" for god sake.
If they were all that dangerous, little kids wouldn't be able to buy 'em and there'd be a disclaimer on the box saying "use at risk of death/demonic possession/eternal damnation".
Plus if a group tries using an ouija board blindfolded, and gets an impartial friend (who isn't touching the glass) to note down the letters that come up, you end up with a load of meaningless rubbish.
Thus, it is far more likely that the subconscious minds of the people touching the glass are causing the ordered letters to be pointed to, rather than some kind of magical entity with horns.
In this day and age I’d expect most of you to have more common sense than to believe in superstitious non-sense. Does anyone still believe in braking mirrors for 7 years bad luck? I would hope not. What about worrying on what side you cross a black cats path?
Belief and faith is useful in certain areas, but in a context like this, it's dumb time wasting and shouldn't be given a second thought.