|That arrow is the mouse pointer making the entire area clickable.|
BackgroundPaul Fitts was an Air Force officer who, during the 1950s, developed models of human movements that are now primarily used in human-computer interactions and aviation.
This is CNNThis morning, I was on CNN.com looking at a photo gallery when I noticed that my mouse pointer had changed from its typical pointer to a thin arrow. Depending on which half of the screen I moused over, the arrow either pointed to the right (indicating that I could click to go to the next photo) or left (previous).
I haven't seen a lot of good use cases for changing the mouse pointer icon via CSS (HTML). Up until now, the best one I've seen is of a hand "grabbing" to indicate that a UI element is draggable.
The beauty of CNN changing the mouse pointer is it makes the entire image, and the area around it, a target without adding a new UI element. A large target, nearby, is one key to good UX. It's what makes the corner pixels on macOS such a great target since the corner pixels effectively have dimensions that are infinite in length. This is why the screen corners are commonly used as a quick way to invoke the screen saver and lock your computer.