After more research, I'm almost certain that they use the syndicated bing search instead of just using the API. Meaning they earn revenue for pure search, but I

After more research, I'm almost certain that they use the syndicated bing search instead of just using the API. Meaning they earn revenue for pure search, but I'm not sure if they still have to pay for some advanced parts of the API (filtering, autocomplete, etc). There's also no way to check if the revenue share dropped, which could be make sense considering how the price hike for the API. So take my comment with a grain of salt!