EXTRA : The GUID
In the time that I've been hacking (and I've been hacking for quite a while), I've heard people refer to and call the GUID everything from "guild" to "gwid".
It isn't a word, it's an acronym and therefore spoken as G - U - I - D. The term stands for Global Unique ID".
What is it? Your The Sims game refers to every object in the game (including the Sims themselves) through a unique 8 digit name that is made up of letters and numbers (GUID expressed in hex), and no two objects should ever share the same GUID or the game will either crash and burn to the desktop, or your computer will blow up.
How are GUID's assigned to objects? First off, Maxis (creator of The Sims) assigns a GUID to each object that comes with your expansion packs; so we don't worry about that. What we do have to worry about is when we clone a Maxis object to make it different, or better. Most of us don't even think about it when we clone, because Transmogrifier (Tmog), the program 99.9% of us use to clone and then create new objects from the bases, assigns a completely unique GUID to the clones at the time of cloning and incorporates your Magic Cookie number into the GUID.
How does Tmog do that? Tmog takes your Magic Cookie number, "makes up" a 2 digit set and sticks it in front of your Cookie number, and then it makes up a second 2 digit set and places it after your Cookie number. The result is an 8 digit (or 4 bytes) GUID. As an example, I'll use my Cookie number for a "pretend" object I cloned. Take a look at the diagram below: