[hi-v-rocknroll]

It goes back much farther than that as it's a practice of successful business people since time began. One much older example of it in written form would Napoleon Hill 1928 "Lesson 9: The habit of doing more for than paid." What it comes down to is cultivating customer goodwill by offering additional value that doesn't cost a lot to encourage more sales via network effects as referrals, and in the modern era, 5-star ratings and shares on social media.