Most (if not all) other cultures kiss just twice, once on each cheek. I'm a first generation Canadian (mom is Dutch), and always thought it's so funny how it's almost a RULE when greeting a Dutch relative. Anyone know the historical significance of this?
There really isn't a historically significant reason or cause for the habit of kissing three times; in fact, the habit seems only have to spread widely in the North of the Netherlands only after 1980 or so, while before that people would kiss just once or twice, or only shake hands.
One theory is that kissing three times is something that started in the French countryside ( the campagne) and then gradually spread northward, but according to an expert on Dutch etiquette the habit was already prevalent in the Southern part of the Netherlands. These regions (Brabant and Limburg) are culturally more Catholic, and also the people there are, according to stereotype, more gregarious than us stiff Northerners. In that case, three kisses signify enthousiasm and intimacy. As social norms became looser in the North, the habit of kissing three times spread there too.
As a direct inspiration for the habit spreading, people have pointed either to a strong representation of Catholics in the Van Agt-government ( in power in the late 1970s), or even a group of high school students at the elite Barlaeus College in Amsterdam.
However, nobody knows for sure what the origin is. It's a social norm now but these are subject to change as in any society, so it may very well be that we won't be doing it 100 years from now.
Sources consulted (all in Dutch, obviously)