Two quick points: First is that anytime you read someone using phrases like 'smoking ecigs' or 'ecig smoke' it is a pretty solid indication of bias against ecigs in general. Electronic cigarettes have no smoke. That is the whole point. They have a pretty benign vapor of propylene glycol (which, as was mentioned above, is used in asthma inhalers and many other things, and has a lot of true medical studies regarding its use), with trace amounts of nicotine and flavoring.
Second, for those who think that nicotine is pure evil, even in the tiniest amounts, well I hope you never eat tomatoes, potatoes or eggplant as they all contain nicotine. In fact you are ingesting significantly more nicotine in an eggplant dish that you would from breathing the second hand vapor from an ecig. http://www.huffingtonpost.com/2012/06/15/nicotine-in-vegetables_n_1597087.html (In that article they mention that 10 grams of eggplant has the nicotine equivalent to 3 hours of second hand smoke.) Nicotine has a pretty well understood effect on the body, although many studies look at inhaled smoke as the mechanism for intake. Without smoke, nicotine is about on par with caffeine as far as its harmfulness. (A side note, there is also something about how Americans process some tobaccos that make them worse for you. For instance American chewing tobaccos are really bad for you, and are known to cause some horrific mouth cancers, yet Swedish snus (which is prepared with just tobacco, water and salt) does not, or at a much reduced rate. Sweden has the lowest cancer rates in Europe, in part because Swedes use snus instead of smoking.)
I should point out that I no longer have a horse in this race. I smoked off and on for years and years, and also used snuff (the old fashioned nasal variety) and snus (the swedish oral kind). I switched to ecigs about 2 years ago, found them delightful, and cut all the other actual tobacco forms out of my life. Then sometime around last Nov., after tapering my nicotine content down gradually in the ecigs, I cut them out too. Ecigs are amazing. Period. (Although not all are created equal. As with most things, do some research and buy quality, both in equipment and in juices. There are a lot of excellent resources out there (forums and such) to help point you in the right direction and away from crap like 'blu'.)