It really depends. IMO, unless its between family, its a way to increase intimacy while staying on the side of respectful. Its more than a hug, but less than a passionate kiss. In situations where a relationship is still developing, it can be a way to 'test' the recipient's level of attraction. I agree with everyone who says that, at minimum, it means the person giving the kiss likes the person being kissed.
I wonder how many of you have had your hand kissed? Do you find it more or less intimate than a cheek kiss?
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh