The title Much Ado About Nothing is very apt, or appropriate, for the play because there is actually a pun found in the title and once this pun is understood, the pieces and themes of the play fall nicely into place. As author A. R. Humphreys states, due to pronunciation, the word "nothing" would have been heard by the Elizabethan audience as "noting" (as cited in Chidester, "Much Ado About 'Noting'"). Noting can refer either to paying attention to something, or heeding it, but it is also slang for eavesdropping ("Themes," eNotes). Hence, while the title is suggesting that the play depicts a great uprising about absolutely nothing at all, due to the pun made with the word nothing the title also suggests that the play concerns a great uprising about things noticed or about things overheard.
All throughout the play, we see that the characters derive opinions about each other based on what others have noted, or noticed. One example is that when Claudio first begins to fall in love with Hero after meeting her, he asks his dear friend Benedick if he had "noted," or noticed "the daughter of Signior Leonato" (I.i.138-139). Benedick replies that he had not really noticed her, even though he had "looked on her" and continues to criticize her in the way that a man who is a "professed tyrant" to women would do(140-151). Later, Claudio allows his opinion of Hero to be influenced by what Don John says he has noticed of her, namely that he has heard rumors that she is promiscuous (III.ii.85-87). Claudio also bases his opinion of Hero on what he believes he has noticed about her, namely that he believes he has seen her with a man in her bedroom window. Since Claudio is basing his opinions on what he believes he has noticed or what he believes other characters have noticed, we see that the term noting directly refers to the play's theme of appearances vs. reality.
Noting, in the sense of eavesdropping also plays a huge part in the development of the play and the play's themes. Not only does Claudio base his opinions of Hero on what Don John has said he has overheard about Hero, we also see love being born from eavesdropping. Benedick is set up by the other characters of the play to overhear Don Pedro, Claudio, and Leonato saying that Hero has informed them that Beatrice is in love with Benedick. Beatrice is likewise set up to eavesdrop on Hero's and Ursula's discussion of Benedick's love for her. Overhearing about their love for each other, as well as a discussion of their faults, tricks Beatrice and Benedick into falling in love with each other. Hence, we see that noting, or eavesdropping, plays a significant role in the plot's development.
Hence, we see that the play's title Much Ado About Nothing is very appropriate because the play revolves around noting in both the sense of what others notice and in the sense of eavesdropping.