The MailScanner anti-spam/anti-virus system will add the word {Disarmed?} at the start of email subjects if it has detected and disarmed potentially dangerous HTML content in the email. These include such things such as "WebBugs" (where spammers can tell if you have read the email message and therefore know that you read spam), iFrame tags (where the email actually "pulls in" pages/files or viruses from an internet website), script tags and Object Codebase tags (where the email contains Javascript or "Object" tags which could harm your machine) and Form tags (usually used by "phishing" spams which ask you to enter your credit/debit card details in a form in the email). Sometimes these tags, such as the "WebBugs" small images, are used legitimately but MailScanner is unable to tell whether or not it is being used legitimately or not and so will "err" on the side of caution and disable the content "just in case". This is called a "false positive"