>Just as many incorrect american expressions have received validation from common usage, it appears that "de nada" may have become an "approved" expression. Both my textbook and dictionary use that form rather than "por nada."
Right. I've seen that before, even though the expression does not make grammatical sense.
"Once again, we come to the Holiday Season, a deeply religious time that each of us observes, in his own way, by going to the mall of his choice." -- Dave Barry