PixelBlock – a Gmail extension that blocks marketers from tracking when you open/read an email

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Everything we do seems to be tracked these days, even when we open our emails. According to Wired.com, “Marketers—or anyone who’s inspired to snoop—simply insert a transparent 1×1 image [pixel] into an email. When that email is opened, the image pings the server it originated from with information like the time, your location, and the device you’re using.” This type of tracking is legal (Google even has a support page on how marketers can do this) and there are many pixel tracking entities out there. PixelBlock is a Chrome Gmail extension that will block these tracking attempts. I’ve added it to Chrome and the above is a sample email in which the tracking was blocked as indicated by the slashed red eye. If you are like me and want to discourage such tracking, and you use Gmail on Chrome please visit PixelBlock to add this extension.

10 thoughts on “PixelBlock – a Gmail extension that blocks marketers from tracking when you open/read an email”

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  2. I believe that, at the very end of 2013 (December?) Google changed how they handle linked graphics that make both this plugin and webbugs in email useless in the manner cited in the writeup. In fact, the Wired article only focuses on a completely different aspect: that it shows you which company attempted to track the email (which Google’s normal GMail system would render useless anyway).

    They now prefetch all inbound graphics and store them in a proxy server. Thus there’s no way to know if the email was read, or even if the email address is valid. For the end user, graphics can now be displayed without concern. That coincided with GMail displaying images rather than the prior behavior of having the option to display images that you had to click.

    I don’t know if it works for IMAP (using a client on your computer or phone), but this extension won’t run there anyway.

    1. (To be clear: the “completely different aspect” the Wired article focuses on is also from a completely different extension covered in the same article, Ugly Mail)

      1. The Wired.com post was written in March of this year and does focus on an extension called Ugly Email which simply identifies emails that are being tracked in your Gmail. The article also goes on to explain that instead of just identifying emails that are being tracked, you could also block this tracking by using PixelBlock. The whole article seems to be saying that pixel tracking does currently exist in Gmail and offers ways to identify the emails that are being tracked or to simply block them altogether. Are you saying that this information is not correct?

        I found the same information on CNET also from March 2015 indicating that pixel tracking does currently exist in Gmail and addresses ways to block it. See http://www.cnet.com/how-to/avoid-message-trackers-in-gmail/

        1. This is straight from Gmail:

          “How Gmail Makes Images Safe:

          Some senders try to use externally linked images in harmful ways, but Gmail takes action to ensure that images are loaded safely. Gmail serves all images through Google’s image proxy servers and transcodes them before delivery to protect you in the following ways:

          -Senders can’t use image loading to get information like your IP address or location.
          -Senders can’t set or read cookies in your browser.
          -Gmail checks your images for known viruses or malware.

          In some cases, senders may be able to know whether an individual has opened a message with unique image links. As always, Gmail scans every message for suspicious content and if Gmail considers a sender or message potentially suspicious, images won’t be displayed and you’ll be asked whether you want to see the images.”

        2. I am saying that. Hang on…

          Looking into it, it’s a mixed bag. Here’s the original announcement of proxy (and I nailed the date!):


          However, it has been determined by researchers that the proxy occurs at the first *opening* of the email (see link below). That means that webbugs can still track that *somebody* opened that email (or a forwarded copy), but only on the FIRST viewing (Mail Chimp notes that, see below). They also no longer get your browser and system information at all, thanks to Google proxying the image. Of course, there’s a setting in Gmail to not display images at all — and since big graphics or background graphics can be tracked, you’d need to do that anyway if you really want to be secure. As an example, I myself track emails by the logo we put in each message, not a 1×1 pixel image. I do it just to verify trends and make sure the messages went out correctly, not to drill down to find information about people; I’ve never used things like the details of the computer that opened it or even look at any individual email, so Google hiding that information doesn’t much matter.

          As it appears that PixelBlock does not block all images (and it would need to), it still doesn’t reliably block tracking of email. You need to turn off the display of images entirely (as Mail Chimp notes in the below link, that prevents it entirely). If you’re okay with them only knowing the first time you opened the email and blocking the details of your computer, Google’s proxy works for that.


  3. Does this also apply to gmail that is not opened within Chrome or another browser.

    My gmail is opened by Apple’s Mail program.

    1. Sandee – this is a Chrome extension only specifically for use with Gmail. However, you can still limit tracking within Gmail itself by going into the settings and under Images select “Ask before displaying external images”.

      If you wish to find something that works for another browser, you’ll have to do a Google search on pixel blocking type extensions or add-ons to see what is available for them as I am not familiar with them.

  4. @Kathleen
    Fascinating. I’ve limited any external images opening with my mail because they slowed it down. Now I’ve got a second benefit.

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