Now, if you search for your favorite local restaurant, bar, business and the like on Google; Google may show you a phone number in the knowledge graph top box that is clickable. When you click the phone number, it will dynamically open up Google Hangouts and let you dial them via your computer to make a reservation, appointment or a complaint.
Here is an example of a popular kosher steakhouse in New York City. I searched for the name of the restaurant and added phone to the query. Google gave me this large box with their number:
Clicking on it launches Hangouts:
Then it will ask if you want to dial the number via Google Hangouts and if there is a fee:
When you say “call” it will try to connect you:
Once connected, you will hear the person on the other end of the call and be able to have your conversation via the computer audio and microphone. I tried this but hung up once connected: