First of all, awakeFromNib is called on every object that is initialized or referenced from within a nib file.

from Apple dev docs

awakeFromNib
Prepares the receiver for service after it has been loaded from an Interface Builder archive, or nib file.

some quora answers:

http://www.quora.com/Cocoa-API/What-is-the-difference-between-initWithCoder-initWithNibName-and-awakeFromNib