Spell Economy
From Drunkapedia
Removed from the game in June 2002.
The Spell Economy was a unique feature of Asheron's Call that determined the effectiveness of spells depending on the use of the spell on a server-wide scale.
One example of a spell that was over used was Flame Bolt V that degraded the spell badly. To counter this at the time, Turbine added the spell Dark Flame as a quest.