A popular study showed that kissing as a greeting is healthier than a handshake because you don't know what someone has just been touching.
What we call the 'Eskimo kiss', or rubbing noses is called a kunik
by the Inuit. It is an expression of affection, usually from an
adult to a child. The Inuit also kiss on the lips as we do. The myth
of rubbing noses grew out of a Hollywood silent documentary.
French disagree on the number of greeting kisses, but mostly for
central France it's two kisses, and for the North, four. There are
exceptions - in Finistère, one kiss is normal - and even disparities
within the same area: half the population of Calais prefer deux
bises, while the other half will greet you with quatre. The number
of kisses can depend on whether someone is a friend or family
member, and varies between generations. To the upper-class French
any more than two kisses is a faux pas.
Of course, it is not just in France that people greet each other
with a kiss; in the Netherlands three is normal, and in Belgium it's
one kiss for your peers, but if someone is 10 years older than you,
then three is respectful. In Spain, two is normal, but you must kiss
the right cheek first.
The French don’t necessarily French kiss more than anyone else; the
term probably comes from our belief that French sexuality is more
sophisticated. In France, it's known as baiser anglais ('English
kissing'), baiser florentin (Florentine kiss) or rouler une pelle
(to roll a spade). In Quebec, it is frencher.
Kissing in public is illegal in India and a similar law has been
proposed in Russia and Indonesia.