This article needs additional citations for verification. (January 2019)
Web tracking is the practice by which operators of websites and third parties collect, store and share information about visitors’ activities on the World Wide Web. Analysis of a user's behaviour may be used to provide content that enables the operator to infer their preferences and may be of interest to various parties, such as advertisers. Web tracking can be part of visitor management.
Uses of web tracking
The uses of web tracking include the following:
- Advertising companies actively collect information about users and make profiles that are used to individualize advertisements. User activities include websites visited, watched videos, interactions on social networks, and online transactions. Websites like Netflix collect information about what shows users watch, which helps them suggest more shows that they might like. Search engines like Google will keep a record of what users search for, which could help them suggest more relevant searches in the future.
- Law enforcement agencies may use web tracking to spy on individuals and solve crimes.
- Web analytics focuses more on the performance of a website as a whole. Web tracking will give insight on how a website is being used and see how long a user spends on a certain page. This can be used to see who may have the most interest in the content of the website.
- Usability tests is the practice of testing how easy a design is to use. Users are observed as they complete tasks. This would help identify usability problems with a website's design so they can be fixed for easier navigation.
Methods of web tracking
Every device connected to the Internet is assigned a unique IP address, which is needed to enable devices to communicate with each other. With appropriate software on the host website, the IP address of visitors to the site can be logged and can also be used to determine the visitor’s geographical location. Logging the IP address can, for example, monitor if a person voted more than once, as well as their viewing pattern. Knowing the visitor’s location indicates, besides other things, the country. This may, for example, result in prices being quoted in the local currency, the price or the range of goods that are available, special conditions applying and in some cases requests from or responses to a certain country being blocked entirely. Internet users may circumvent geo-blocking and censorship and protect personal identity and location to stay anonymous on the internet using a VPN connection.
A HTTP cookie is code and information embedded onto a user’s device by a website when the user visits the website. The website might then retrieve the information on the cookie on subsequent visits to the website by the user. Cookies can be used to customise the user’s browsing experience and to deliver targeted ads. Some browsing activities that cookies can store are:
- pages and content a user browsed.
- what a user searched online.
- when a user clicked on an online advertisement.
- what time a user visited a site.
A first party cookie is created by the website the user is visiting. These cookies are considered "good."
A third party cookie is created by websites other than the one a user visits. They insert additional tracking code that can record a user's online activity. On-site analytics refers to data collection on the current site. It is used to measure many aspects of user interactions including the number of times a user visits.
Restrictions on third-party cookies introduced by web browsers are bypassed by some tracking companies using technique called CNAME cloaking, where a third-party tracking service is assigned a DNS record in the first-party origin domain (usually CNAME) so that it's masqueraded as first-party even though it's a separate entity in legal and organisational terms. This technique is blocked by some browsers and ad blockers using block lists of known trackers.
- Canvas fingerprinting allows websites to identify and track users using HTML5 canvas elements instead of using a browser cookie.
- Cross-device tracking are used by advertisers to help identify which channels are most successful in helping convert browsers into buyers.
- Click-through rate is used by advertisers to measure the number of clicks they receive on their ads per number of impressions.
- Mouse tracking collects the users mouse cursor positions on the computer.
- Browser fingerprinting relies on your browser and is a way of identifying users every time they go online and track your activity. Through fingerprinting, websites can determine the users operating system, language, time zone, and browser version without your permission.
- Supercookies or "evercookies" can not only be used to track users across the web, but they are also hard to detect and difficult to remove since they are stored in a different place than the standard cookies.
- Session replay scripts allows the ability to replay a visitor's journey on a web site or within a mobile application or web application.
- Web beacons are commonly used to check whether or not an individual who received an email actually read it.
- Favicons can be used to track users since they persist across browsing sessions.
- Federated Learning of Cohorts (FLoC), trialed in Google Chrome in 2021, which intends to replace existing behavioral tracking which relies on tracking individual user actions and aggregating them on the server side with web browser declaring their membership in a behavioral cohort. EFF has criticized FLoC as retaining the fundamental paradigm of surveillance economy, where "each user’s behavior follows them from site to site as a label, inscrutable at a glance but rich with meaning to those in the know".
Web browsing is linked to a user's personal information. Location, interests, purchases, and more can be revealed just by what page a user visits. This allows them to draw conclusions about a user, and analyse patterns of activity. Use of web tracking can be controversial when applied in the context of a private individual; and to varying degrees is subject to legislation such as the EU's eCommerce Directive and the UK's Data Protection Act. When it is done without the knowledge of a user, it may be considered a breach of browser security.
In a business-to-business context, understanding a visitor's behaviour in order to identify buying intentions is seen by many commercial organisations as an effective way to target marketing activities. Visiting companies can be approached, both online and offline, with marketing and sales propositions which are relevant to their current requirements. From the point of view of a sales organisation, engaging with a potential customer when they are actively looking to buy can produce savings in otherwise wasted marketing funds.
Users can control third-party web tracking. Opt-out cookies enables users to block websites from installing future cookies. Websites may be blocked from installing third party advertisers or cookies on a browser which will prevent tracking on the users page. Do Not Track is a web browser setting that can request a web application to disable the tracking of a user. Enabling this feature will send a request to the website users are on to disable their cross-site user tracking.
Contrary to popular belief, browser privacy mode does not prevent (all) tracking attempts because it usually only blocks the storage of information on the visitor site (cookies). It does not help, however, against live data transmissions like the various fingerprinting methods. Such fingerprints can be easily de-anonymized. Many times, the functionality of the website fails. For example, one may not be able to login to the site, or preferences are lost.
Some web browsers use "tracking protection" or "tracking prevention" features to block web trackers.
- Behavioral analytics provides insight into the actions of people when they are online, usually when they purchase products online.
- Consumer Data Industry Association
- Employee monitoring is the use of workplace surveillance to gather information on the activities and locations of employees.
- Gemini space and Gopher as alternatives serving mostly textual content without tracking
- Google Chrome#User tracking concerns
- GPS tracking can track the location of an entity or object remotely
- Internet privacy is the level of privacy an individual has while they are connected to the internet 
- Internet tracking
- Information privacy
- Network surveillance
- Track and trace is used to track a product's status and monitor their location when transported
- Web analytics is the reporting and analysis of website data to improve the user's experience 
- Web beacon is an invisible graphic that is placed on a website to monitor the behavior of the user visiting.
- D. Sundarasen, Sheela Devi (2019-04-08). "Institutional characteristics, signaling variables and IPO initial returns". PSU Research Review. 3 (1): 29–49. doi:10.1108/prr-10-2016-0003. ISSN 2399-1747.
- "Internet Safety: Understanding Browser Tracking". GCFGlobal.org. Retrieved 2019-12-13.
- Valentino-DeVries, Jennifer (2019-04-13). "Tracking Phones, Google Is a Dragnet for the Police (Published 2019)". The New York Times. ISSN 0362-4331. Retrieved 2020-10-23.[dead link]
- Kleinberg, Samantha; Mishra, Bud (2008). "Psst". Proceeding of the 17th International Conference on World Wide Web - WWW '08. New York, New York, USA: ACM Press: 1143. doi:10.1145/1367497.1367697. ISBN 9781605580852. S2CID 15179069.
- "What is Usability Testing?". The Interaction Design Foundation. Retrieved 2019-12-13.
- "What is an IP address?". HowStuffWorks. 2001-01-12. Retrieved 2019-12-13.
- "How cookies track you around the web & how to stop them". Privacy.net. 2018-02-24. Retrieved 2019-12-13.
- Martin, Kirsten (2015-12-22). "Data aggregators, consumer data, and responsibility online: Who is tracking consumers online and should they stop?". The Information Society. 32 (1): 51–63. doi:10.1080/01972243.2015.1107166. ISSN 0197-2243. S2CID 205509140.
- Loshin, David; Reifer, Abie (2013-01-01), Loshin, David; Reifer, Abie (eds.), "Chapter 4 - Customer Lifetime and Value Analytics", Using Information to Develop a Culture of Customer Centricity, Morgan Kaufmann, pp. 23–31, ISBN 9780124105430, retrieved 2019-11-11
- "Online Trackers Are Now Shifting To New Invasive CNAME Cloaking Technique". The Hack Report. 2021-02-27. Retrieved 2021-04-14.
- Dimova, Yana; Acar, Gunes; Olejnik, Lukasz; Joosen, Wouter; Van Goethem, Tom (2021-02-23). "The CNAME of the Game: Large-scale Analysis of DNS-based Tracking Evasion". arXiv:2102.09301 [cs.CR].
- Andrea Fortuna (2017-11-06). "What is Canvas Fingerprinting and how the companies use it to track you online | So Long, and Thanks for All the Fish". Retrieved 2019-12-13.
- BigCommerce (2019-12-12). "What is cross-device tracking?". BigCommerce. Retrieved 2019-12-13.
- "What is online tracking and how do websites track you?". Koofr blog. Retrieved 2019-12-13.
- "Cookies - Definition - Trend Micro USA". www.trendmicro.com. Retrieved 2019-12-13.
- "Session replay", Wikipedia, 2019-10-15, retrieved 2019-12-13
- "FullStory | Build a More Perfect Digital Experience | FullStory". www.fullstory.com. Retrieved 2021-04-05.
- Goodin, Dan (2021-02-19). "New browser-tracking hack works even when you flush caches or go incognito". Ars Technica. Retrieved 2021-02-21.
- source.chromium.org https://source.chromium.org/chromium/chromium/src/+/master:components/federated_learning/. Retrieved 2021-03-04. Missing or empty
- Cyphers, Bennett (2021-03-03). "Google's FLoC Is a Terrible Idea". Electronic Frontier Foundation. Retrieved 2021-03-05.
- Mayer, J. R.; Mitchell, J. C. (May 2012). "Third-Party Web Tracking: Policy and Technology". 2012 IEEE Symposium on Security and Privacy: 413–427. CiteSeerX 10.1.1.388.5781. doi:10.1109/SP.2012.47. ISBN 978-1-4673-1244-8. S2CID 14652884.
- "Website visitor tracking going too far?". Prospectvision.net. Retrieved 2012-08-03.
- "What is an Opt Out Cookie? - All about Cookies". www.allaboutcookies.org. Retrieved 2019-11-11.
- "Firefox 42.0 release notes".
- "What is the Definition of Online Privacy? | Winston & Strawn Legal Glossary". Winston & Strawn. Retrieved 2019-12-13.
- "Web Analytics Basics". www.usability.gov. 2013-10-08. Retrieved 2019-12-13.
- Beal, Vangie. "What is Web Beacon? Webopedia Definition". www.webopedia.com. Retrieved 2019-12-13.
- "Princeton Web Transparency & Accountability Project (WebTap)". Retrieved 2018-02-20.
We monitor websites and services to find out what user data companies collect, how they collect it, and what they do with it. With our measurement platform, we study privacy, security, and ethics of consumer data usage
- "OpenWPM – A privacy measurement framework". Retrieved 2018-02-20.