Obviously Google does a ton (and a half) of these tests, most of which never go further. But Sergey pointed out several other interesting tests last week.
This one, however, particularly interested me because it highlights reviews AND because it is one more of the Google”down the rabbit hole”, keep them here or nowhere type tests. Google either wants a users time or their action. And doesn’t want other sites to get credit for the activity.Mobile Knowledge Panel Tab Test by Mike Blumenthal