In the past the idea behind the clue-by-four was that you were beating some sense into the hittee. Unfortunately it was later discovered that being hit on the head with a large wooden plank with "CLUE" written on it actually caused a loss of brain cells in the hittee. When you consider that the original intention of the hitter was to provide the hittee with some in the first place, this then put the hittee in a deficit of brain cells. Life, the universe, and everything being what it is, likes to be in a state of balance. So in order to solve the problem of the brain-cell deficit, the hittee would proceed to ask ever increasingly stupid questions causing the original hitter to smack his or her head against a wall, therefore restoring the balance.
For the purpose of beating sense into people, the clue-by-four was replaced by a large foam clue bat which has much the same result as the clue-by-four except does not kill what few brain cells the hittee may or may not already possess. Though the tool of choice now is the foam clue bat, the clue-by-four is still in regular use. It was renamed to the "Luser Attitude Readjustment Tool" which was then shortened to LART.
The key difference between the two tools, though they have the same origins, is what implications of being hit by one might have to your standing in the community that you are a part of.
To be hit with a large foam clue bat signifies that the hitter believes you are being immensely stupid and need correcting in a way that you will never forget, for your own good. Being LARTed is somewhat more common despite it's neurological implications and the fact that it is generally more serious. To be LARTed means that the hitter believes you have done or said something mind-bubblingly stupid and must be punished for your crime. You are not expected to gain anything from the experience as no friendly "constructive criticism" or advice will be given with the LARTing.
It has been theorized is that being hit by a clue-by-four only dislodges the slower, denser brain cells allowing the faster, smarter brian cells more chance of forming rational thought. The tests, however, have been inconcluive; showing positive results in only 42% of subjects.