I went with "other". I, personally, like fogging as a verb - it is so similar to one of my favorite words (fog the censors). As for the noun, I like fogger, but wouldn't want to steal Janty's word, but I like Kate's "old foggies" too.
And to borrow an idea from Sheakespeare; would that which we call an e-cig not smell as sweet by any other name?
When I tell people about it, I call it an electronic cigarette because it is simple, but I take it apart and explain the function of each part before demonstrating it and letting them smell the vapor. The response is usually quite positive

. I did have one recent quitter tell me they resented my fogging in a 12 step meeting because they really wanted to smoke and can't do that at a meeting

. I offered to share mine, but they wouldn't even try it. I also offer to share my vapor quite frequently. I figure I would have shared my cigarette with these people if they asked, and what the heck, maybe I will create another foggin' fool like me.
Thanks, Kate, for the e-....
