Pixel tracking is when an obscure image is sent in the body of an email to gather information about the recipient.
Use Cases and Examples
Pixel tracking is prevalent in the world of digital advertisement. Service providers typically use it when they have limited access to end users' devices or software tools.
An example of pixel tracking is when it's used to know when an email is opened. The sender of an email will usually attach a small image that might not be visible within the email, and when the reader's email client requests the image it forwards their client and request header info to the email sender.
There are many ethical issues with this, and many other services exist to combat this. For example, many email clients do not download images within an email until the user consents to download them. Gmail also loads up images using a proxy service. In this case, the proxy and not the user's details is forwarded to the email sender.
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