It depends on the tone of voice of the person asking. I usually reply that it is an electronic cigarette and I have haven't touched a real cigarette in X days (22!)... if they're interested, I'll tell them how it works and about the different juice types, that it's only water vapour, not smoke, that it's healthier than smoking etc etc etc but it depends on their interest. If they're smokers and they say they'd like to think about getting one, I'll give them my name and tell them to add me on FB so we can talk about it more.x