Hi!
Well, it's a very nice introduction. You could add more comments on the kinds of values you can store into the keys. Keys can hold String, Binary, Dword, Multi String, Expandable String. Then you can explain what are each one, and what are their uses.
Also, you could bring an example of where can you find IE's url history (HKEY_CURRENT_USER\ Software\ Microsoft\ Internet Explorer\ TypedURLs). Or where the setting for the pretty wallpaper we have on our desktops are stored.
You could add where the registry resides (on disk; file names, on memory).
Many more things can be said about the registry, but with caution as not to grow company hackers.

Robert