I often draw a parallel between hookahs and pv's. They are MUCH more closely related than cigarettes and pv's. I do so when describing them to people who are curious about my ecig set up, and they, almost all of them, are instantly more receptive to the idea and the unusual shape (Not looking like a cig). I describe it as 'a portable, personal, electronic hookah'. And it makes perfect sense to everybody who I've said it to.
I have believed this for quite some time now, and the big-cloud segment of vaping plays to the same aesthetic as hookah smoking.
Why? A hookah is only an immobile pipe (as in pipe-smoking) with a water-cooling device strapped onto it. We don't water-cool our vapour, and we don't use desk- or floor-standing devices with flexible pipes or multiple heads.
Because the function of a hookah and an ecigarette are almost identical. The cloud produced by a hookah is almost entirely created by the "juice" the tobacco is saturated in, which is largely glycerine and flavorings. The tobacco itself is not burned but baked, which vaporizes the nicotine. As a result hookah smoke contains little tar and far fewer toxins than burned tobacco (more than vaping though).