What is the advertisement wall in qq?

There are many kinds of advertisement walls, but now it is common for everyone to set up a QQ to represent a school or a whole. You can add QQ friends directly, so that you can post white information directly, and the person in charge of this QQ will sort out this information and post it directly in QQ space, so that everyone can browse some advertisement information directly.

Say that you have a secret crush, but you are embarrassed to tell her face to face, then tell each other through this advertisement wall, which can be anonymous directly or not.