Kathryn Schulz has a nice New Yorker piece, “What part of ‘No, totally’ don’t you understand?,” that focuses on the odd affirmative use of “no” seen in this snippet of conversation:
MARON: They can look at any painting and go, “Eh.” They can look at a Rothko and go, “Hey, three colors.” And then you want to hit them.
DUNHAM: No, totally.
She finds some similar examples (“No, definitely.” “No, exactly.” “No, yes.”) and writes:
At first blush, “no” does not appear to be the kind of word whose meaning you can monkey with. For one thing, there is its length. At just two letters and one syllable, it lacks the pliable properties of longer words. You can’t stuff stuff inside it. (You can say “unfreakingbelievable,” but you cannot say “nfreakingo.”) You can’t mangle it, à la “misunderestimate” or (the finest example I’ve heard lately) “haphazardous.” On the contrary, it is so simple and self-contained that it is a holophrasm, a word that can serve as a complete sentence.
Shoot, there aren’t any open pubs in Canterbury at this hour.
Yes, there are.
Is Chaucer drunk?
Yea, and passed out on the table.
Is the Tabard open?
Nay, it closed at midnight.
Isn’t Chaucer meeting us here?
No, he went home to bed.
When it comes to explaining the affirmative-no phenomenon, however, things get murky. She quotes unnamed “linguists I spoke with” as claiming that “this use of ‘no’ might be a response to an implicit or explicit negative in the preceding statement,” but this strikes me as so clearly wrong I’m surprised any linguist would suggest it. And “the theory I like best”—that “No, totally” is really a contraction of “I know, totally”—is just silly. But the whole thing is enjoyable and worth reading, and there’s more discussion at the Log.