Answer:
Clutch drag is when the clutch pedal is fully depressed and the clutch is still partially engaged. When the clutch pedal is released or in the up position the engine is connected to the transmission input shaft. When the pedal is depressed or in the down position the engine is disconnected completely from the transmission. When the clutch drags it is still partially attached to the engine. A dragging clutch can cause a glazed flywheel and premature failure of the clutch. It will also cause the syncros to work twice as hard to slow down or speed up a gear inside the transmission when shifting. Basically syncros will wear out faster than normal and may not work properly depending on how bad the clutch drag is.
from http://answers.yahoo.com/question/index?qid=20081004220833AAf5EFu