Please bear with me as I am not an English expert, only an aspiring amateur!
I'm mostly aware of the rules regarding punctuation and quotes. Something like the following sentence makes sense to me:
She was so rude that I felt compelled to say, "I hope you act that way toward everyone."
However, where I get confused is when quotation marks are used simply to emphasize a single word or phrase:
Nobody really knew what he meant by "feature".
(I'm not really sure what to call this use of quotation marks. Is this still a quotation?) Should punctuation go inside the quotation marks?
I should clarify that I am interested in the common or accepted American usage.