The integrator was written by: Christopher L. Greer (AKA Siginet of msfn.org). Christopher is the owner of a computer company in Southern California called Professor CPU. The RVM Integrator was written for use with an UpdatePack and an AddonPack created by: Ryan VanderMeulen (AKA RyanVM of msfn.org).
The UpdatePack was created to allow users to actually Directly Integrate Windows hotfix updates into your Windows Installation CD. It does not integrate hotfixes using the normal Microsoft /integrate switch. It actually replaces older windows files with newer ones and slipstreams the hotfixes into your disk like microsoft should have originally done in the first place. This method will significantly save tons of space on your disk and allow you to have room to add more AddonPacks (3rd party applications and tweaks) as well.
The AddonPacks are used to put 3rd Party Applications and Tweaks to your disk. There are many different types of AddonPacks and you can learn a lot more about them on RyanVM's forums. They allow you to add things like AntiVirus, AntiSpyware, DVD Burning software, Windows Themes, registry tweaks... and so on and so fourth. There are even AddonPacks made to remove things from your disk, like unwanted files in the i386 directory, or Windows Messenger. The possibilities are almost unlimited.