I'm a big fan of them, too. The Friends Chats and Clan Chats came about AFTER I first started playing. Before then, unless there were players in the area skilling with you, skilling like mining or woodcutting and such was a lonely experience.
Now, you can engage in lively chat in RuneScape via fc and cc even if you're in a lonely skilling spot trying to get XP for the next two hours. Makes the time pass much better when you've got people to chat with, whether those players are in the same location or not.