Gun control activists raised concerns in 2011 that KSL Classifieds did a disservice to its community by providing a marketplace for sellers who were not licensed dealers , as such sellers need not perform background checks on buyers . A 2011 report from the office of New York City mayor Michael Bloomberg found that KSL Classifieds had more gun listings than any other general-purpose online marketplace , exceeded only by online marketplaces that specialize in guns . KSL Classifieds discontinued gun listings in the wake of the Sandy Hook Elementary School shooting
Sandy Hook Elementary School shooting
Sandy Hook Elementary School shooting
KSL Classifieds