Rather than gathering statistics and managing cookies for each server independently, the company can analyze all this data together, and track the behavior of individual users across all the different websites, assembling a profile of each user as they navigate through these different environments. But the company could use web beacons requesting data from its one image server to count and recognize individual users who visit different websites. For instance, each server could be specific to a given website, and could even be located in a different city. This company could store all of its images on one particular server, but store the other contents of its web pages on a variety of other servers. As an example, consider a company that owns a network of websites. Once a company can identify a particular user, the company can then track that user's behavior across multiple interactions with different websites or web servers. Since beacons are not just embedded in visible content, and can be embedded in completely invisible elements, a third party can gather information even if the user is completely unaware of the third party's existence. This means a third-party site can gather information about visitors to the main sites, such as a news site or a social media site, even if users are not clicking on the third party's ads or other content. This request will require the user's computer to supply identifying information about itself to XYZ Widgets, not the host server.
When a user opens the page, the user's computer will send a request to download the advertisement from the page's host server, but will then be referred to XYZ Widgets' server, to which it will request to download the image. In this scenario, an advertisement for the fictitious company XYZ Widgets which is displayed as an image on a web page would not have its image file residing on the page's host server, but rather, on a server belonging to XYZ Widgets. The beacons are embedded in an email or web page as images or buttons or other HTML elements, but they are hosted on a different server from the website where they are embedded, and it is to this third-party server that requests and identifying information are sent. This protocol allows companies to embed beacons in content that they do not directly own or operate, and then use such beacons for tracking purposes. As part of that request, the user's computer then has to supply identifying information to the third-party server. To do so it has to send a request to the third-party server to ask it to send the referred content. When a user sees the email or the web page, the user's email reader or web browser prepares the referred content for display. Framing allows web pages to refer to content such as images or buttons or HTML elements that are located on other servers, rather than hosting this content directly on their own server. The use of framing added a new level of versatility to web beacons.
The host server can store all of this information, and associate it with a session identifier or tracking token that uniquely marks the interaction. The identifying information provided by the user's computer typically includes its IP address, the time the request was made, the type of web browser or email reader that made the request, and the existence of cookies previously sent by the host server. Currently, these can include visible elements such as graphics, banners, or buttons, but also non-pictorial HTML elements such as the frame, style, script, input link, embed, object, etc., of an email or web page.
This basic technique has been developed further so that many types of elements can be used as beacons. This request provides identifying information about the computer, allowing the host to keep track of the user. When a user opens the page or email where such an image is embedded, they might not see the image, but their web browser or email reader automatically downloads the image, requiring the user's computer to send a request to the host company's server, where the source image is stored. The image could be as small as a single pixel (a "tracking pixel") and could have the same colour as the background, or be completely transparent. The first web beacons were small digital image files that were embedded in a web page or email. They can also be used to see if an email was read or forwarded or if a web page was copied to another website. A web beacon is any of several techniques used to track who is visiting a web page.