Unwanted by a user could be considered trash.
It is why people want a Star Wars, or Marvel category. To them, those topics constitute trash/litter.
To others, they are treasure.
If you put one of your UofU shirts in my car, I would find that to be trash, even though to you it is a perfectly acceptable shirt. If you kept putting your UofU gear in my car, I would lock you out of my car, or otherwise limit your access to it.
Why should CougarBoard be any different? If Cougar Board is intended to be fun and relaxing, why would you not try to make it the best experience it can be?