You see these in a lot of places. Sometimes it is obvious what they are, but not always. For instance, this one is my favorite, a set of handbills rather than just one, I’ve seen it most recently in the office of Toven d’Cannith.
I have no idea what these notes are discussing, but it surely does seem fascinating. Is that a playbill on the left? maybe a menu on the right? And a Polaroid of something in the left lower center? I wonder what the Eberron version of a Polaroid would be – certainly something made by House Cannith, right?