Better the Spam, Stringent the Gmail Filters

Every body receives spam, and what I have noticed the amount of spam in Gmail is larger than other popular free email services. But this does not deters us and Google because the 'better and complex the spam, more stringent is Gmail' . Here is a live example of the exemplary nature of Gmail spam filter.

Just check out this screenshot. If you are a frequent mailer, you would have noticed the Message with the same Header at least once.

This is the default Gmail email not delivered email header. You get such emails when an email you sent is not delivered, because the email address is unreachable or the ID does not exists.

This Message was retrieved from the SPAM folder from my Gmail but still Google was skeptical about it and had indicated that it is not a genuine mail. This was actually caught by the Google's Online Phishing Filter (Read more about this).

Had this Mail not filtered out by the Spam Filter, how to notice that it is a Phishing email?

The answer is as simple as it can be. A common observation would have revealed the true nature of email. Now as this mail shares the same Header as the Gmail's official 'Not Delivered mail', so all you have to do is to check the details of the Mail.
You can clearly notice that the mail is sent by some arbitrary website and not Google. Check the snaps below.

This is SPAM Mail

This is a Genuine Mail

So keep in mind all mails that look alike are not always the same.

Related : Google Tweaks Gmail a little