How to use Gmail filters to control spam

Using Gmail filters to control spam
Brian Gongol

One of the problems with spam filtering is the presence of "false positives": Good e-mail that is wrongly flagged as spam.

As the volume of unsolicited mass e-mail (spam) rises, so does the risk that even good spam filters will occasionally flag a good message and prevent it from getting through.

One of the most widely-used e-mail services is Gmail, which includes what is generally a very good set of spam filters. However, Gmail does catch a few false positives. That means that Gmail users have to check their spam folder on occasion just to scan for those false positives.

However, a simple trick involving Gmail's user-created filters can help speed up this process considerably.

Step 1. Create a label

From any page within Gmail, open the "Labels" tab

Labels

Scroll down and select the link titled "Edit labels"

Scroll down and in the box beneath "Create a new label:" type in "Spam------------------" and click on "Create":

Spam label

Be sure to include all of the trailing dashes -- these are what makes the label effective.

Step 2. Create a subject filter

From any page within Gmail, click the "Create a filter" link:

Create a "Subject" filter containing the following (just copy and paste from within the red box), then click on "Next Step":

You'll be pushed forward into a new screen, where you'll use the drop-down menu to select your "Spam------------------" label. Click on the checkbox to the left of the drop-down menu, then click on "Update Filter":

Step 3. Create a word filter

Just as in the step above, click on the "Create a filter" link:

Create a "Has the words" filter containing the following (just copy and paste from within the red box), then click on "Next Step":

Step 4. Watch your e-mail life improve immediately

Since much spam is generated by "zombie" computers that have been hijacked by viruses and other malware, the messages they send out don't change. By creating a "Spam------------------" label, you won't interfere with Gmail's ability to identify and filter spam, but you will make it easier for yourself to scan your spam folders in order to do a better job of catching those false positives. Here's how your spam folder will look after you apply the "Spam------------------" label:

A double-filtered spam folder

See how easy it is to know which messages to examine a little more closely -- and which ones are the same-old, same-old? The dashes literally move the known spam out of the main column, making it vastly easier to quickly scan for false positives. Of the 12 messages here, all but two can be discarded without even a second look.

Note: The "Has the words:" filter list was updated on August 22, 2007. It appears to filter out about half of all spam being generated right now.