Actually i'd not heard of them to be honest. By my definition "truly" hardcore are those guilds who got either world firsts, or region firsts.
Anyway, with regards what is important or relevant to this thread, I don't think a little digression is going to hurt when put next to the massive unicorn posting from HackieDoodle.
The actual conversation I wanted you to continue was what you, consider to be hard content in WoW. You mentioned C'Thun and AQ40 a few times, but I wanted you to go into more depth, as I still maintain that EQ1 content was not even in the same league of difficulty, based on the mechanics and era it was played in.
Care to elaborate?