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 and personal scale. If a spell was not used often, the power of the spell increased above the normal level.
If a spell was over used, either by the whole server or by casting the spell in rapid time, the effectiveness of the spell decreased.
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.