Nowadays,　abundance　of　Web　applications　offers　flexible　and　convenient　services　for　users.　Although　almost　all　Web　sites　have　their　own　privacy　policies　and　declare　that　they　won＇t　disclose　users＇　privacy　without　their　consent,　users　may　still　receive　spam　messages　after　they　register　or　interact　with　some　sites.　Obviously,　commercial　interests　can　drive　some　sites　to　disclose　users＇　privacy　such　as　email　addresses　to　third　parties.　In　this　paper,　we　propose　a　collaborative　method　to　identify　Web　sites　that　disclose　users＇　privacy　by　using　a　privacy　disclosure　finding　protocol　inspired　from　secure　multiparty　computation　(SMC).　The　advantages　of　our　method　are　that　the　method　can　identify　privacy　disclosure　sites　while　preserving　volunteers＇　privacy　and　that　the　method　uses　a　collaborative　approach　without　relying　on　a　trusted　third　party　which　makes　it　practical　in　the　reality　of　Web　based　services.