Be careful with this... It is the vapor salesman's false pitch. Nicotine is a known neurotoxin, it increases inflammation, lowers your hdl, raises your ldl, and stresses your endocrine system (adrenal et al.). While ecigs may deliver fewer toxins than analogs, that doesn't erase the fact that you are much better off without nicotine.
Unless there's a demonstrable, important (life affecting) effect, I wouldn't care too much about nicotine. Maybe some people are even naturally balancing some of their brain chemistry with it.
I wouldn't surprised if in 30 years we 'discover' that nicotine was okay all along, just like eating fat.
By the way, what is your opinion on caffeine?
I miss the neurostimulant effect badly... if you are right about nicotine being exonerated, I'll jump for joy and pick some up that day.