Although not quite related to travel, I once worked as a web master/web applications developer for a site that was being used to in conjunction with an collegiate academic study to study the usefulness of using a web-based approach to help smokers quit smoking. More specifically, to help female smokers quit smoking.

What I learned from this study (even though I was in an IT role) really opened up my eyes. Yes, quitting smoking is hard to do, but it requires both willpower as well as (at least a slight) adjustment to the smoker's lifestyle.

The results of the study were used in a Psychology dissertation by one of my group mates. PM me if you are interested in reading it.