This has already been discussed at length. Spoiler tags will do more harm then good here. It'll just give stupid users a reason to spoil and then try to justify it. As Kraco said, users who dont like preview discussion are in the minority, and there isn't too much preview discussion really, except maybe in the less mainstream stuff in General Anime. If you happen to be in that minorty, well, sucks to be you then. You'll just have to be careful i guess.