They are a new technology from China that simulates the act of smoking and can deliver nicotine in a way that doesn't involve combustion, known carcinogens or tar.
There are few studies about vaping ('smoking' electronic cigarettes) so vested interests can't make claims about health or effectiveness but anecdotal evidence suggests that it's much better for quitting and cutting down on smoking tobacco than approved nicotine replacement products.
If you'd like to know more about this technology which could potentially save billions of lives then these forums are great sources of information and activism to keep the practice legal:
The vaping community is new and enthusiastic so please excuse evangelism, we are just keen for other smokers to be able to benefit as we have.
It would be fantastic if Stephen could spare a few minutes to consider the value of an effective smoking replacement and the need to work towards proving health and cessation effectiveness. We need all the support we can get as authorities are clamping down worldwide on vaping with the rationale that it's not proven effective and safe. In fact it has not been proven unsafe either but smoking has for sure.