Wait... People actually think it looks cool? I don't smoke, and never have. My entire life I've been surrounded by people that vilify smoking, and yet somehow I think smoking cigarettes looks cool. E-cigs thought? Nope. Completely ridiculous. I'm amazed at how popular they are. I can think of three stores in my city that specialize in them.
Like the article says, it's a pretty new thing among teenagers. This contradicts what pabs has said, but in my school it's definitely a big trend. No one I know of has been judged for smoking an e-cig too harshly, and there's definitely no exclusion going on...but that's just the difference in school and location.
I think they somehow tie in nicely to the whole "steam punk" aesthetic. I think that while genre looks ridiculous, but to each their own.