[riffic]

you can choose any directory you want and while FHS is a recommendation there's no one forcing you to use it.

Note that more often than not I'll often argue for sticking with FHS and it's a good rule of thumb to know the rules first before you go breaking them. However in my opinion /srv isn't a pragmatic choice to make in a demonstration and it's for the sake of clarity I can see why the writer would just say /websites. In your own implementation you can put your content wherever you want.