Where is the Billboard slide I submitted being displayed?
There are several ways to tell where a slide is displayed, aside from going and looking at the actual screens.
Go to the Community area, and click on the "My Slides" tab (you need to be the submitter and be logged in). From there, you will see a list of the slides that you have submitted. Clicking the down arrow to the right of the "Added" column will bring up details about the slide, including the "Slide Usage" information at the top.
You can go to the Billboard Screens list. This page lists all the units, and their screens separated by building. If you click on a screen, it will tell you what slides are currently being displayed.