Actually nicotine is apparently not the addictive part of smoking, rather other chemicals in tobacco are.

Anecdotally I can confirm I've smoked e-cigarettes quite heavily for a few months then stopped cold turkey and had zero withdrawal or cravings, but I occasionally feel a desire for smoking a cigar quite strongly despite having them at a rate averaging a few a year.

EDIT: Not majorly addictive, rather than not addictive at all.

[ref]:http://www.gwern.net/Nicotine

And fructose.

http://vimeo.com/30397537#t=40m00s