There's little research on how safe they might be or whether they're an effective strategy for kicking the habit, but more people are giving e-cigarettes a try every day.

About one in five adult cigarette smokers in the U.S. had tried electronic cigarettes in 2011, nearly twice as many as in 2010. Sales reached nearly $500 million in 2012 and are expected to double to $1 billion this year. As the market grows, even tobacco companies are jumping on board.

R.J. Reynolds Vapor Co. launched its Vuse electronic cigarette this summer in Colorado. Altria Group Inc., parent company of the nation's largest cigarette maker, Philip Morris USA, will soon debut its product, MarkTen, in Indiana.

Electronic cigarettes, or e-cigarettes, are a smoke-free alternative to the traditional paper cigarette. The most basic version, one that could be mistaken for an actual cigarette, is comprised of a liquid cartridge attached to a white cylinder containing a battery.

The battery heats the liquid into a vapor that the user inhales. Instead of smoking, it's come to be called "vaping."

Eoin Treacy's view The business of supplying nicotine to addicts has long been seen as distasteful by many investors because of the high proportion of deaths directly attributable to smoking. On the other hand, the reliability of cash flows from tobacco businesses have offered attractive yields for just as long.

The question many have been asking is how much of a challenge the evolution of e-cigarettes represents for traditional tobacco companies. The fact that they are moving into this niche suggests they see a future in it, but let's take a look at some of the shares.

Over the years tobacco related conglomerates have also been able to build up substantial non-tobacco related businesses. For example, Kraft was originally part of the Philip Morris group (today's Altria) and the company still has a substantial holding in SAB Miller. The share (Est P/E 14.33, DY 5.13%) trended consistently higher from early 2009 until last year when it lost momentum. It pulled back below the 200-day MA last week and a clear upward dynamic will be required to check potential for a further test of underlying trading.

Altria's non US tobacco businesses are represented by Philip Morris International (Est P/E 15.73, DY 3.97%). The share also lost momentum from mid-2010 and is falling towards the lower side of an 18-month range. It will need to hold above $82 if Type-3 top formation characteristics, as taught at The Chart Seminar, are to be refuted.

British American Tobacco (Est P/E 15.23, DY 4.53%) is dual listed in the UK and South Africa and has a wide number of foreign listed affiliates. A 30% holding in India's largest company, ITC, is among the most notable. The London listing posted a large downside weekly key reversal in May and will need to sustain a move back above 3500p to offset current score for a further test of underlying trading.

Imperial Tobacco (Est P/E 10.42, DY 5.54%) has been trending lower since testing the 2600p level in July 2012. The share found at least short-term support last week near 2100p but will need to sustain a move above 2400p to break the progression of lower rally highs to suggest a return to demand dominance beyond the short-term.

Japan Tobacco (Est P/E 14.69, DY 2.66%) had developed a considerable overextension relative to the 200-day MA by May and has been ranging in a process of mean reversion since. A sustained move below the trend mean, currently near ¥3200, would be required to question medium-term potential for additional upside.