It is said that the "nothing" in "much ado about nothing" has a double meaning. When pronounced, it is similar to "noting" which apparently means rumors or gossip. So the meaning of the title could be either "much fuss about nothing of importance" or "much fuss about gossip."
I have no read the play, but I have seen the film and I did not notice this at all. But Shakespeare is known to play with words that can have more than one meaning.