[B-Con]

You can't install unofficial packages via pacman. And AFAIK none of the unofficial/AUR package managers, like yaourt, are in the official repositories so the point where you cross the line is very clear and distinct and any wiki guide to installing from the AUR makes it clear you are going into unofficial territory.

I haven't used Manjaro but they seem to intentionally hide the distinction between the official and unofficial repos, which is a bad idea.

[gmueckl]

Also, yaourt has a lot of warnings and prompts at each step along the way to make absolutely certain that you understand what you're getting yourself into with the packages you're installing. The process is certainly not for beginners. Ubuntu seems to go for a more user friendly process instead.