It was the Samsung Galaxy Note Edge, which had a curved edge that would behave as a separate/complementary display.
The fact that it didn't caused much buzzed aside from making some headlines is a good indicator that it wasn't well received, mostly because it had a priced tag that would rival most high end consumer tablets/laptops.
I'm not sure if this was more of an experiment, or a really bad hit or miss. Google is known for providing experimental products (the google glass being a well known one), so not sure if this was the same thing for samsung.
But we have to admit that the concept of having a separate yet embedded display to allow for additional functionality is a pretty cool concept, but guess will need to wait and see who's able to really deliver it