Craig Harkins posted a screen shot on Twitter of Google testing placing the hotel booking feature at the top of the search results, as opposed to under the right panel in the local knowledge card for the hotel.
Here is a picture of the test, which shows the booking ad at the top (click to enlarge):
Here is how it normally looks, on the right side (click to enlarge):
I guess Google is testing to see if they get more bookings by moving it from the right side to the top of the page. I suspect they are getting more bookings.
Forum discussion at Twitter.
