its related to database table redundancy removal and transitive dependencies maintaining referential integrity.
Here is your answer(commonly accessible information will be better left without normalization as normalization increases number pf joins ):
*www.25hoursaday.com/weblog/2007/08/03/WhenNotToNormalizeYourSQLDatabase.aspx
guess reading this might help:
*en.wikipedia.org/wiki/Database_normalization
Normalization is a must, unless u are creating some simple application.
Consider this tutorial(worth reading):
*phlonx.com/resources/nf3/