Roy Castillo is a Filipino computer programmer from Danao City, Cebu who graduated from Informatics Computer Institute SM Branch. He discovered a bug in Facebook which allows him to took advantage of a cross site scripting vulnerability (XSS) that allows outsiders to add script to Web pages. His status "Off to Danao City" swarmed some Facebook users because it couldn’t be deleted, and Roy couldn’t be blocked — because he wasn't in the friends lists of the profiles on which he appeared. Some said they tried deactivating and reactivating their Facebook accounts to get rid of him — it worked for one commenter, but not for others.