False Positive Emails

Today I dug out a very important email from my mailbox from the SPAM folder. As I had guessed it, it was 'False Positive Filtering'.

In the simplest terms, False +ve emails are those which should have hit your inbox but the spammer algo with your email provider thought it was a spam. So, how does this work? Usually most sites such as Google, Yahoo etc keep their spammer rules very secretive for security reasons.

Common possibilities are these:
- When the email's HTML contains links to images with names remotely suggestive of porn stuff
- Many spam emails ask user to explicitly click on link 'remove me from this list' only to trap their email and domain names to send more spam. So, sometimes, even genuine emails with 'remove me....' can be considered spam
- If the sender's email domain address does not match the 'From' string. For e.g. if the mail says From: Income Tax Dept' and domain is 'gxbvghh.com' . Sometimes genuine emails, which are sent as mass mails using a 3rd party provider can get flagged as positive.
- Suggestive attachment names

Interestingly there is a metric to measure email deliverability and one of them is to reduce false positive emails. I believe Google has it highest at around 99%.

So, look for those missing emails in your bulk/spam folder.