I wondered what this trend was. Back when I was i college, I worked in a lumber mill. Now, in a lumber mill, smoking is a bad idea, but folks were allowed to smoke - in the break rooms.
I was the only guy in the crew that DIDN'T smoke. So lunchtime was a bit "hazy" for me - fourteen people smoking in a 10x15 room means a LOT of smoke. I am forever cured from wanting to smoke, or from minding at all about cigarette smoke. Aversion therapy, I think they call that.
Anyway, I have seen folks sucking on these things and breathing out some sort of vapor, but I had no idea what it was. Thanks for cluing me in.