IMDB Across Devices

Why do my IMDB "Recently Viewed" searches not appear across all of my devices such as PC / Tablet /Phone when I am signed in to my IMDB account on all devices? When I enter a search on my PC I would like to be able to refer to it on one of my other devices. For example, when I sign into a streaming service on my PC, I can add to or view my saved Watch List on all of my other devices.