Web tracking

Web tracking is the practice by which operators of websites 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:
Methods of web tracking.
IP address.
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.
HTTP cookie.
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:
First and third party cookies.
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.
Controversy.
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.
Justification.
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.
Prevention.
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.
The Firefox and Microsoft Edge web browsers use "tracking protection" or "tracking prevention" features to block web trackers.