The point of an Emerald Nuts ad campaign a few years back. There's a bizarre scene, for example, two guys circling each other in shopping carts proclaiming "My name is Norman and I am great!" "No, I'm a better Norman than you!" The tagline: "Egomanical Normans love Emerald Nuts!" There were quite a few variants (Elegant Naysayers, Evil Navigators, Extinguished Novelists, etc), and the campaign built up to a Super Bowl Special in which Eagle-eyed Machete Enthusiasts Recognize ALittle Druid Networking Under The Stairs.
There was an Amstel (beer brand) campaign some years ago whose ads consisted of really funny songs, like "Amigo Mío, Sólo Tú Encuentras Leña" (My Friend, Only You Find Firewood) or "Amigo Mío, Si Te Echaras Laca" (My Friend, If only You Wore Hairspray). Of course, the point of the ad was how great Amstel was for sharing with your friends.
A commercial for Staples features a law firm that decides to abbreviate their name in order to save ink when printing their name. Unfortunately, their firm's name is Dudley-Irwen-Newberg-Gonzales-Brown-Anderson-Taylor & Stein.
The candy bar PB Max had a campaign somewhat similar to Emerald Nuts, with ads illustrating what the "PB" in the name did not stand for - "Penguin Black Belt" or "Plywood Bobsled" for instance. "PB" actually stood for "peanut butter", by the way.
The cell phone manufacturer HTC has a television ad featuring a Hipster Troll Carwash.
Adidas campaigns have used backronyms such as All Day IDream About Sports.