This seems especially important since in most of the country right now, all restauraunt business is takeout.

The short version:  When you look up a restaurant’s phone number in the Yelp app, Yelp gives you the option to call for “Delivery or Takeout” or “General Questions.”  If you choose General Questions, it calls the restaurant directly.  If you choose Delivery or Takeout it calls Grubhub, which then reroutes your call to the restaurant.  You are none the wiser because this rerouting happens automatically.  Then Grubhub charges the restaraunt 15-20% of your order total for this “service”.   Oh, and they record your phone call too.

Please read the article for details as well as more Grubhub financial chicanery.