This is a seldom discussed area of "popular" music that is surprisingly important in pop culture.
For as long as there have been radio and later, television, there have been "jingles" that were written and recorded to promote various products and services. For the most part, the jingles are designed ONLY to sell the product. They need to be memorable, but they generally are not designed to be pop music hits on their own.
But some of these jingles take on a life of their own and actually do become pop hits.
One of the most famous examples is Coca-Cola's "I'd Like To Teach The World To Sing" during the early 1970s. One of my first memories as a child was watching this commercial on TV and digging the catchy tune. The tune obviously struck a chord with listeners because not long after the Coke commercial was run, the song was recorded (with new lyrics that don't mention Coca-Cola) by a band called the New Seekers and became a huge hit.
Anyone else have examples of similar phenomena?
Interesting coincidence: a few years ago, I was working late one night and had the radio tuned to an oldies station. As I popped open a bottle of Coca-Cola, this song started playing on the radio.