Just my opinion, but I would hope that topics could be structured in a way that important components to the endings of dramas are not revealed. For example, I just started Mouse, but from this topic I now know that at the end one of the leads will have become bad. That kind of ruins it for me, and I'm not sure if I will keep watching it.
Of course there is the spoiler button, but that doesn't really work if the topic has already given away some of the ending. Putting the title of the drama in a spoiler line kind of defeats the purpose of the thread. A better approach is to make sure the topic does not disclose the ending in any meaningful way.
Again, just my opinion. I'm sure there are others who feel differently.