That's actually pretty tough to define. It's one of those things, I know it when I see it. I guess the closest I can come is any topic that has a wider context. Some threads that are currently in GC are ones I would define as ID topics, like the 9/11 thread and the one about natural disasters. They're not as lighthearted as normal GC discussions and have ramifications on a large scale.

~DragonHeart~