I tend to view hardcore/casual in terms of difficulty of content.

Hardcore content = content that is difficult, takes many runs to master, one mistake and the raid wipes, requires alot of tactics, thought, and strategy to complete, and content that takes longer than 30 minutes to complete. People who like this high difficulty content are "hardcore" to me. EQ1 was hardcore, requiring 72 (I think) person raids into a dungeon that lasted 6-8 hours.

Casual = easy mode. Sorry. Casual content is easy content that takes 30 minutes to accomplish, usually requires very little if any, tactical thought, and "hardcores" can steamroll through this content in a few hours after it's released.

I think most 30ish year olds were around in EQ1s heyday. They know what hardcore is. Now, with this new generation, they have no idea what hardcore is because they we're around when MMOs where hard as hell and required more thought than what is common today.