When I peer mentored new international graduate students at Kent State, they often were puzzled by many aspects of American English, but the greeting ritual known as "How are you?" seemed to particularly baffle them.
The literal meaning of the question didn't puzzle students; it was how Americans utilized it. Some Americans didn't wait for an answer, confusing the students, while other Americans reacted strangely when international students started to provide a detailed answer to the question, letting students know that some conversational norm had been violated.
Though most Americans know the ritual (usually something like "Hi, how are you?", "I'm fine. How are you?", and "I'm all right, thanks."), it is odd if one thinks about it. Linguists would describe the ritual as phatic communication, an empty type of talk that we do to keep communication means open for when we do have something worth saying. Why it takes the form of a question and answer is beyond me (though I'm sure some American Studies scholar has an answer that will bring in democracy, the pioneer spirit, and jazz or something). Why ask how someone is if one doesn't really care or want to really hear the answer? Anything outside of "well" or whatnot tends to be regarded as a violation of the little ritual, unless the conversation partners really know one another well (say, spouses), in which case, an answer such as "fine" might be viewed as too minimalistic a report.
I tend to just say hello for a phatic greeting, but if someone asks me how I am I perform the ritual.
Lately though I've noticed a related phenomenon, primarily in writing and not speech. In an email, people seem to skip the "how are you?" ritual. It seems to be replaced by a line, often near the end of the message, along the lines of "Hope you're doing well."
This is interesting because rather than ask someone how he or she is, the writer skips the issue entirely and just lets the reader know that he or she cares (even if, like in many "how are you" exchanges, he or she doesn't). It also provides a clue to relationships between parties. Aside from a newcomer to American English, a classic tipoff that someone doesn't like you is when you ask "How are you?" and the person answers but doesn't return the question. This is probably unconscious, but as psycholinguist (in the sense that he's a psychologist interested in language, and not in the sense that he's a crazy linguist)
James Pennebaker likes to point out, much meaning can reside under seemingly the most insignificant word choices such as pronouns. Therefore, the "hope" line might be regarded as an invitation not to further communicate. Perhaps the writer really hopes not so much that you're doing well, but that he or she will not hear from you again. This line seems to especially pop up when an email conversation could be
generated, but the writer of the email is too busy to pursue it beyond
an initial response but still wants to seem polite. Thus, the lines of communication are kept open in the phatic sense, but in a realistic sense they are being closed. It certainly is more polite than not replying to a message at all.
But maybe I am reading too much into it. In any case, dear reader, I hope that you are doing well.