A tracking pixel is a tiny image embedded within the code of a website or in an email. It is used to collect data about the website visitor or email recipient.

Usually, the image file measures just 1×1 pixels in size. When embedded in the HTML code on a web page or within an email it is generally too small to notice. Additional code is often used to render it completely invisible to the user.

So how does this tiny image learn so much about a website visitor or email recipient?

In the case of a website, images are normally stored on the same server as the files containing HTML code. A line of code refers to the location of an image, which instructs the browser to download the image and display it on the screen.

A tracking pixel is stored on an external server. The user’s browser receives the instruction to download the pixel from this external server and displays it.

Remember, the pixel is so small it is almost invisible and can be completely hidden.

When the pixel is downloaded, the server which hosts it captures certain information about the computer on which it is displayed, such as your IP address.

And when used in conjunction with JavaScript the pixel server can learn even more.

Why use tracking pixels?

A pixel can be used to track things such as which pages a particular user visits on a website. It can also be used to identify which email recipients opened a particular email and even who clicked a specific link within the email.

For this reason, tracking pixels are commonly used in online marketing to help understand the behavior of target markets better. This helps marketers understand what elements in a marketing campaign work best. With that knowledge, they can focus efforts on doing more of what works and stop doing what doesn’t yield good results.

For example, Google Analytics uses a pixel and JavaScript to allow website owners to track how site visitors behave on their websites. The information is aggregated to provide metrics such as the number of site visitors.

It also provides information such as the number of visits to individual pages, traffic sources, and the time spent on a website. This can be useful for a variety of reasons, including determining precisely where shoppers abandon their carts.

Another application is to tailor ads to a specific user based on the types of websites they visit. And you know when you keep seeing ads that appear to follow you around the web? That’s known as retargeting and also uses pixels to work.

Application in affiliate marketing

Pixels are also widely used in affiliate marketing too, such as Amazon Associates. When a website owner signs up to a specific affiliate program they are provided a unique snippet of HTML code to insert in their website.

The affiliate code includes a link that is unique to the website owner. It also often includes a tracking pixel, which allows the number of page impressions can be measured.

To calculate the click-through rate (CTR) you divide the total number of clicks over a certain time span by the page impressions.

This is useful information for a marketer as it provides a baseline CTR at the start of a campaign.

Measuring the CTR after a change will allow a marketer to see directly if it was the right thing to do or not. And that is hugely valuable information to know.