Can I ask what the difference between sociology and anthropology is? As a student of the latter, I was posed this very question by a friend and found myself at a loss on how to truly communicate the difference between the two. The typical response seems to differentiate the two as the study of society and of culture, respectively, but since society and culture intersect at so many levels, is that really even an answer?
If you ask my handy Oxford reference dictionary, it says that social anthropology is ‘the study of the social organisation and cultural systems of human groups’ whereas sociology is the ‘the study of society and social problems’. This is demonstrably uninformative.
I believe the difference is a matter of focus; that both subjects cover many of the same things, but what they are looking for is different. This is where, as you say, the main difference comes in; that is, sociology studies society, whereas social anthropology studies culture. I also agree with you that the level to which these two concepts interact throws into question whether this distinction means anything, however I think there is a subtle difference which could satisfy the curious. Sociology looks at society and how it works, whereas anthropology looks at culture and why it happens. Of course this is an over-simplified answer and there are WORLDS of complexities, but let me go into my initial thoughts a little.