The procedure in question would basically reset your system to the state when you bought your computer from the Store. This was very handy if one wanted to sell the computer without having to reinstall from scratch.
Of course all licensed software needs to be removed first, but the Apple software and system updates remain at their latest version.
Is not really a must have but was very helpful!
I have been able to accomplish this via the following method. I may not be the best idea given it deletes the account while logged in, but worked for me.
1) Do all of the necessary installations, etc. just as under Snow Leopard, using your setupacctname account.
2) Once that is done, BEFORE restarting in single user mode:
dscl . -delete /Groups/admin GroupMembership setupacctname
dscl . -delete /Users/setupacctname
3) Reboot into single user mode (Hold Command-s at startup)
4) Check the filesystem: /sbin/fsck -fy
5) Mount the filesystem: /sbin/mount -uw /
6) Remove the setupacctname directory: rm -R /Users/setupacctname
7) Remove or rename .AppleSetupDone so you get the language choice
mv .AppleSetupDone .RunLanguageChooserToo
8) Delete miscellaneous files (unnecessary, but useful if you're imaging the drive):
rm -R /Library/Caches/*
rm -R /System/Library/Caches/*
rm -R /var/vm/swapfile*
9) Shutdown or restart
I might point out this apple kbase article:
Specifically on how to run dscl in Single User. It says it's for Lion Server, but I had success with it on Lion Client as well. It simplifies your process so you can do the entire process from single user instead of having to do part of it logged in.