KBB (Kelly Blue Book). Example: you want to buy a car, you need the information of the car like price, dealers, engine, tax... and so on. So the KBB is the website which let you to do that, or when you sell a car, you need search about the dealers, and trade your car, the KBB site will support it too. And when the websites want some services like: lead driver, KPO, Price Advisor... So they have to buy the API of KBB company to integrate the services to their website.