Here is a common sense summary; Never fire up your electronic cigarette without getting the consent of those around you or the owner of the property where you are standing.
Where Can You Vape?
2007 saw the emergence of a brand new invention from China; the electro 
nic cigarette. Already sold widely in the United States for some time, this product became available in most states when several companies started to market them on various internet sites nationwide.
Smokers have found the electronic cigarette to be the closest thing to actual smoking as the product looks, feels and tastes like the real thing; even producing a vapor that looks like smoke and gives the smoker the throat hit that they expect and the nicotine that they crave.
Can I Vape Anywhere?
The question is; can I use the electronic cigarette anywhere? The short ans wer is “Maybe”. The vapor produced by the e cigarette consists of propylene glycol (dry ice). This vapor dissipates almost immediately and does not smell as bad as tobacco. There is no passive smoking issue for non-smokers and the vapor does not linger on clothing, hair, or fixtures and fittings which is why the electronic cigarette has been accepted in some bars, restaurants, workplaces and even on board airplanes (sometimes.) Think about it; would you walk into a restaurant and start spraying a fruity aerosol spray? There is still a smell from ecigs.
Always Ask First
From experience, it is always better to approach the bar manager, restaurant owner, etc before using the e cig and showing them that it is not the real thing. Many companies now offer e cigs that are black, silver, red, etc instead of the standard white, so it is obvious to onlookers that the e cig is not real. The standard e cig has a red, led tip that glows when the e cig is inhaled, but many sellers are now offering blue and green led tips so that the e cig does not glow red in the dark and cause problems for the e smoker.
In the Workplace
There are many pubs across the country that have embraced the electronic cigarette and have welcomed the returning “smokers” to their premises. The pub trade has suffered terribly since the smoking ban was enforced and the electronic cigarette offers the pub landlord a real opportunity to get some of that business back. Many offices and workplaces are also welcoming the e cigs. Many companies claim that productivity is up and absenteeism lessened by employers allowing their staff to use e cigs at work.
Conclusion
The real winner, of course, is the smoker. The electronic cigarette is a much healthier, cheaper option than traditional smoking and finally gives the smoker a viable alternative to the real thing. Many are using the device to quit altogether while others are cutting down or using the e cig as a healthier alternative. Being able to smoke indoors in the bitterly cold weather is a massive advantage and negates the need for the quick rushed fag smoked, but not really enjoyed, outside. In the next couple of years, this invention will become much more prevalent and recognizable and those that embrace the invention as a good thing will surely benefit.