I'm an American, and I just returned from spending a little over two weeks in Australia and New Zealand. It was a wonderful trip, and I could go on for ages about all of the amazing things I saw, food I ate, and great people I met. I did notice one thing that I wondered about, and thought this would be a good place to ask. In the US, the proper response to "thank you" is "you're welcome" or "my pleasure." Plenty of people do say, "no problem" "sure thing" or the like, but it is my understanding that these are pretty informal modes response. I have heard people complain (here or elsewhere) about the "no problem" phenomenon, because in response to an expression of gratitude, the implication of "no problem" seems to be "don't worry, you didn't inconvenience me" or "I didn't mind doing you the favor," and neither of these are exactly a great sentiment to express.
However, during my travels in the Antipodes, it was extremely common for people to respond "no worries" or "it's alright." And the people who would respond like this were not just my peers, but also service people at rather fancy hotels, who would have more of a vested interest in retaining some kind of formality.
So, my questions are: is this the common and typical ways to respond to "thank you"? Could my thanks have come off as too effusive? (I thought that once or twice when the intonation of "it's alright" sounded a lot like, "no really, its really alright!") Do people ever say "you're welcome" or does that sound too formal?