If you are sending out a newsletter, you probably know that, even if it is perfectly legitimate, spam filters may block it by mistake. The "false positives" issue is a huge problem for legitimate senders: anti-spam filters have no way of knowing whether a message is spam or not; they can only check whether it looks like spam. They give each incoming message a "spam score", and if the score is high enough the message is redirected to the recipients junk folder or even not delivered at all. Only messages with a low spam score make it to the recipients mailbox. MailingCheck incorporates SpamAssassin engine, which is the most popular antispam filter used by ISPs around the world, and analyzes your e-mail message in order to calculate its "spam score"; based on its content: the higher the spam score is, the higher is the chance that, once the mail has been sent, it will be filtered out as spam. This will allow you to correct any major problem before you actually send out your mailing. MailingCheck can be used by legitimate senders only, in order to track down any problem with their legitimate (opt-in) messages' delivery and comply with SpamAssassin guidelines for senders http://wiki.apache.org/spamassassin/AvoidingFpsForSenders.