anything can be a portal, so long as the one trying yo open it or pass through it has the key. i don't believe the "thing" used is the trick, rather the "who" that is using it. that is to say, someone who is not able to connect with spirit without the board, or any other tool for that matter, will not be able to with it.

GhostGuy wrote on 07/26/12 at 01:44:54:

Some of the horrible experieces with ouija boards deal with a
haunting already in progress. Novice paranormal enthusiasts
will sometimes invite a ghost to not only stay in the residence
but also to make activity which unltimately scares them when they
discover that they aren't as brave as they thought they were.  

Very true. And it's probably more than just some. It's also been given a bad name, many times from people using it who shouldn't be. The media probably has a small role in that.