If there was a bulletin board that was primarily used for activities not permitted by local law, the board would likely be taken down. For example, if there is a bulletin board in a dorm that is used to advertise different drug delivery services in town, either the board will be taken down or a new requirement would be placed requiring all postings to be preapproved.
Craigslist is an Internet bulletin board that chose to remove a few categories due to pressure from law enforcement and the community.