Cookie tracking in advertising and web analytics: January 6, 2013 by Maciej Zawadziński Chief Executive Officer
Cookies were invented in 1994 by Lou Montulli and John Giannandrea, at that time an employees of Netscape Communications. Since then cookies become an inseparable element of every ad technology.
Why cookies are so important? Where do they fit in today’s advertising ecosystem? Are they replaceable? What is the future of cookies?
Cookies were used widely for the first time in advertising by DoubleClick (which at that time was called Internet Advertising Network) back in 1995 in order to rotate banners (today we would call it frequency capping - limiting number of times showing the same ad to one visitor) and quickly become adopted by other players on ad technology market.
The scope of usage of cookies, against consumer privacy concerns, widened pretty fast. The most popular cases for using cookies are:
In ad technologies and web trackers in general, the most common approach is to store in the cookie unique identifier of the visitor (usually UUID, but not necessarily). All information gathered about this particular visitor (called Visitor profile) is stored on server side in a format optimised for fast lookups, e.g. in a key-value/nosql database, a memory cache or at least an indexed column in sql database.
Visitor profile consists of information valuable to the advertiser, publisher or other ad ecosystem party (check out this interactive ad ecosystem map). Depending on tracking system it can range from timestamp of latest visits to the website, list of visited pages, time spent on pages, list of viewed/clicked ads as well as those ads that user engaged with (e.g. with interactive content), up to demographic profile, behavioural data and any other, useful for targeting and/or statistics information.
Cookies are widely used in advertising for nearly 2 decades, but they become less reliable, and there are more and more issues with using them, such as:
However, there are techniques to track visitors regardless of cookies, such as browser fingerprinting – see the Panopticlick experiement to check how unique is your browser (mine is unique in 2.6+ millions!), or cookie respawning, a technique in which in case cookie was not found (user possibly deleted it) tracker logic tries to restore it from alternative places where it saved the visitor profile id such as flash cookies or HTML5 local storage.
There are already (not yet desperate) efforts to look for alternatives. IAB (Internet Advertising Bureau) have it’s own Advertising Technology Council (ATC) with The Future of the Cookie Working Group working on cookie alternatives that would be more reliable, universal (suitable for use not only within web/mobile web, but also for in-app advertising) and can be easily widely adopted by ad technology suppliers as well as do not raise privacy concerns. See presentation below for more information:
This is the first post in the series of online tracking and exploring today’s ad ecosystem, stay tuned for more!