Contrary to traditional log analyses, the foundation of page tagging as a cross-server method was laid in the 90s by so-called web bugs, known as tracking pixels or pixel tags. These single pixel graphics, which were added to the HTML code and could initially only be viewed by website visitors, offered a convenient solution for tracking the frequency of page visits. If a user called up the respective page, then the tracking pixel, which was located on an external server, was downloaded. This made it possible for providers to collect, store, and analyze data for their customers.
Around the millennium, page tagging web analytics were optimized, by making the pixel tags invisible and adding JavaScript Code to them. These tags are also added to the HTML documents, revealing information about the requesting client (visitor’s browser). This allows website operators to find out which operating systems visitors are using, where they originally come from, and which keywords brought them to your website. In case the client deactivated JavaScript, then only the tracking pixel is downloaded. This only registers the page visit, so no other user or device details can be followed.