Well made points, but I'll respectfully disagree. If education is the goal, I find calling it a PV or APV much more useful in most of the conversations I have about the subject. Take two conversions as a "for instance:"
"What the heck is that thing?"
"It's an e-cig?"
"Oh, one of those fake cigarette things." <--- just about every single time.
"Well, no it's not really like a cigarette."
"Looks like you're smoking to me."
"No, it's vapor, not smoke."
"Then why's it called a cig?"
"That's just what they call it. But it's not. Really."
"Yeah, ok."
"No really! It's not."
"I believe you."
"No you don't. You made a face!"
"That's my I believe you face."
"LIES!"
or
"What the heck is that thing?"
"It's a Personal Vaporizer."
"Oh... a what?"
"Personal Vaporizer. It produces vapor instead of smoke."
"Right. What's the difference?"
"Well, vapor is like what comes off of a tea kettle. Smoke is like what you get off your BBQ grill."
"So it's like smoking?"
"Sort of, but it's called vaping. No smoke, just steam."
"Is it dangerous?"
"I dunno, but I drop several hundred deadly poisons, carcinogens and chemicals by using this thing. And it tastes way better, as well. I vaping caramel right now."
"Huh. Cool!"
My experience has been that calling it a vaporizer leads to much more interesting and in-depth discussions about what I'm doing. Calling it an e-cig tends to shut people's mind down with the "it's just a fake cigarette" mentality.
Your mileage may vary, of course.

But put simply, I don't smoke any more. I vape.
I'll be happy to educate anyone on the difference.