As with Public Notices, if flyers are spread or advertisements put up in a specific location, you don't know about it unless you've been to that location IG or it makes sense for you to know about it (finding a flyer in the Crone for a gambling tournament when you sleep in the Crone, being told by someone else IG about a particular bulletin, etc.).
This board is primarily for quick little "selling/seeking this-and-that" posts without the fear of sending major event threads or political publications to the next page. Anything that you want to organize quickly and don't mind the original post of being lost forever later on is also fine for this board.
This board's inactive content is automatically deleted at regular intervals. Even so, don't emote responses in a forum reply -- do it IG! Also avoid replying unless asked by/cleared with the original poster or getting an OK from a DM.