Only Sixteen" benefits society by communicating valuable lessons not only to young teenagers, but to their parents as well. The narrator in this song is a teenager himself, though, as he points out (no doubt a little tongue-in-cheek), he is a much wiser 17 now. This line can be taken at face value, or perceived as slightly satirical depending on the audience.

If the listener is a teenager, then the message seems to be that even if a love goes sour, there are lessons to be learned from mistakes you make in life. Not only this, but it encourages them to continue on trying for love even if you are disappointed the first time as long as the lessons learned are heeded in the future. The lesson of this love is not that the girl in question was too young by being only sixteen -- how could she be when the narrator was sixteen himself and clearly in love? The message is that you shouldn't give your heart away too quickly, instead you should wait and see if the person you are opening your heart to is capable of accepting it. Of course this message is important for teenagers just starting out in the world of romance, but this song has a much wider appeal.

The more interesting message from this song is directed at the parents...

The song is to remind them of the intensity of emotion, the slow drag of time, and the naivete of choices that we make in our youth. Parents often lose sight of what the world was like at sixteen, and how devastating something may seem while you're experiencing it even if it turns out to be a minor event in retrospect. The satire of the lines "(But you were a mere lad of sixteen) / Oh, I've aged a year since then" is aimed not at being facetious, but at reminding parents how one year in the life of a teenage can truly add up to some major changes. Time moves so much slower when we're young, and parents need to remember that when faced with a sixteen-year-old with a broken heart.
Of course, one more thing that raises this song into the realm where it belongs to sit along side these other great works is that the messages it delivers, whether to a teenager or to their parents, is utterly timeless. The lyrics lack any kind of pop culture reference or dated language that might pin it down to a certain era or to make it feel outdated at any time. Cavemen as well as spacemen could sing this song and the audience would still be able to identify with the song. This wide appeal as well as the strength and value of the message this song delivers is what makes this song great, and is one more piece of evidence to prove the greatest of Sam Cooke himself.