There are more than 4,000 residential buildings that use BuildingLink message boards in the Naked City. About 85 percent of them moderate what residents post, with building management serving as arbiter of what’s acceptable 90 percent of the time, according to data from BuildingLink.  A shareholder in a large Upper West Side co-op got miffed when management rejected posts about a school rezoning debate, buildings materials, and a Paris apartment exchange. Should the board establish a policy on what’s considered an acceptable post? Can shareholders request that posts not be subject to management approval?    Read the article……………….