What is a Web Bug/Beacon? Your Ultimate Guide

A Web beacon is a hidden, transparent, but nonetheless “graphic” image that finds its way onto your computer. They’re small “objects” that are embedded into a webpage or an email and are “activated” when you visit the site or open the email.

Web beacons are placed on a website or in an email and they monitor, to a small degree, what you”re doing while you visit the website or send the email.

If you want to see how a website, such as Monster.com, would actually use Web beacons, read our article on Web beacon policy.)

Web beacons are also referred to as “tags,” …tracking bugs,” “pixel trackers” or “pixel GIFs.” They’re invisible because they’re small, typically no larger than 1 pixel x 1 pixel. (Pixel lesson: Short for picture element, a pixel is a single point in a graphic image. Your computer monitor shows images by dividing the display screen into thousands or millions of pixels, arranged in rows and columns.)

The Web beacon shows up in a graphical/picture format called GIF (Graphic Interchange Format), common to the Web. To your browser, it looks just like any other picture or image on a webpage, and your browser doesn’t make a fuss about it. In other words, you and your Web browser simply don’t recognize beacons.

How do Web beacons get on your computer?

A Web beacon gets your computer through an email, or it can be in a webpage that you visit. Some people might call it “spyware,” in that it’s used to take note of your online activity, but in most cases (especially with websites) it’s not there to do any harm.

What are Web beacons up to?

Web beacons track in specific, purposeful ways some of your online behaviors when you receive an email or visit a specific website. Web beacons are custom-made: They are designed to monitor your activity (individually or as part of all website visitors) to give somebody helpful information.

Website owners use Web beacons to know how many people visited their website. And ad networks (advertising companies focusing on the Web) use them to get customer behavior data. They’ll use Web beacons in their ads to get an idea of how often an advertisement is appearing or being viewed. They can also use Web beacons to track an individual’s response to online ads (one by one).

With business emails (that are purely promotional), companies and online marketing agencies want to know if readers are opening the emails they receive. When the Web beacon loads (which happens when the email is opened), the Web beacon is embedded invisibly in the email graphics, so the company can find out if you opened the email, when you did it and so on.

It can gather the IP address of the computer
The URL of the web page the bug is located on
The URL of the page the bug came from
The time the bug was observed
A set cookie value
The type of browser that was used to get web bug graphic image

Going into your browser’s settings to “turn off” (reject) cookies will stop Web beacons from tracking you.

Beacons behaving badly.

Once in a while, Web beacons are used by spammers to confirm the email addresses of unsuspecting users. Once you open an email (that you didn’t know was really spam), the embedded Web beacon sends information back to the sender (the spammer), that says you opened the email, at the same telling them that the email account is valid and active—and ready for more spam or mischief. That’s the reason for that message you get that holds off on showing you the email and asks you if you trust the sender…and why you should take a few seconds to examine every email that doesn’t look familiar or sound quite right.

Catching the beacon’s signal.

There is a way to find out if there is a Web beacon on a webpage you’re visiting, but the process is pretty technical. It has to do with looking at what’s known as the “source code” of a webpage. You can do some research on checking for Web beacons, if that interests you.