In May, Google announced a way to schedule appointments and food delivery directly through Google Maps.
Linda Buquet posted on Local Search Forums that the appointment scheduling seems to be powered by Demandforce.
She explained that Darryl Quinlan posted on Google+ that Demandforce has partnered with Intuit and now Google for online scheduling. Linda dug into a bit and believes this is how Google powers their service.
She said if you look at the How it Works page on the Demandforce, it is the same appointment booking widget shows up in the Knowledge Graph.
Here is a video on DemandForce:
Forum discussion at Local Search Forums.
