Why is LSD good?

I know that LSD is good, but I'd like a little more detailed explanation on what more it does over a regular transmission. Also, what parts does one have that a regular one doesn't

its got something to do with both wheels rotating at the same speed contsantly...u want one wheel spinning faster than the other when coming around corners
*edit*

it's all explained there
http://www.howstuffworks.com/differential.htm

LSD is a must if you want to master the ancient art of Drifting.:D

Isnt that site great for learning basics of mechanics (and other things)...thats where I first learned the concepts behind turbos.