Mobile Tutorial Series – First-Versus-Third-Party Cookies
This piece is designed to give you an introduction to the world of tracking cookies, and the differences between first- and third-party cookies. Cookies have been around almost as long as the web. A cookie is a small text file that is placed on the browser of your computer via your browser, for example, Internet Explorer, Chrome, Mozilla, or Safari, by a website or advertising product to store and transmit information.
Some examples of companies that place cookies on your computer include the websites you visit and advertising companies that display ads to you. We generally talk about two kinds of cookies in digital marketing, first-party and third-party.
First-party cookies are placed on your computer by a site when you visit its pages.
The purpose of the first-party cookie is to help the website recognize a visitor and personalize user experiences to the habits and preferences of that user. First-party cookies can help sites automatically login a person, associate her behavior with previous actions, customize content and experiences to previously expressed interests, and more.
Third-party cookies are placed on your computer by companies other than the web site you visit. Most sites display content from a variety of sources when you request a web page. For example, an ad network might place a cookie on all browsers that are exposed to an advertiser’s banner ads. Or if a site includes “like” buttons or embedded videos, these can also deliver third-party cookies.
Third-party cookies help advertisers track what consumers do after they view or interact with content. This kind of measurement is important because most people exposed to an ad don’t click to make a purchase immediately, or visit an advertiser’s website immediately, but may subsequently visit. Advertisers want to be able to understand these “long-term” advertising effects.
Media companies also use third-party cookie data to develop customer profiles that infer interests and purchase intent from the types of things people do online. For example, an ad network could aggregate all of the people who interacted with baby care ads to create an audience of people who are (probably) parents.
First- and Third-Party Cookies and Cookie Blocking
We’re sure you have heard a lot about cookie-blocking, which some people do to avoid ad tracking.
Third-party cookies collect and pass anonymous information only. A person’s name, address, or data that might identify them as an individual is not passed. Nevertheless, some consumers take steps to avoid even anonymous tracking. Some have started deleting their third-party cookies. They do this using purpose-built tools or manually changing settings in their web browser. Most leading browsers now offer the option of changing settings. Others have chosen to use web browsers like Safari that block third-party cookies by default.
Generally, consumers don’t try to block first-party cookies because they add value to the experience, and because the individual actually chose to visit the site in the first place. First-party cookies can serve great benefits to the consumer, like recognizing them when they revisit a site so they don’t have to log in again. In addition, a consumer that sets their browser to reject first-party cookies will find it very difficult to surf the web because many sites require them in order to gain access to content. You must enable cookies in order to visit the sites in question.
Session Cookies Versus Persistent Cookies
A session cookie lasts only as long as your browser session, whereas a persistent cookie lasts more than one session. Both have uses, but advertisers focus on cookies that persist for a longer period of time — often 7- or 30-days.
Third-Party Cookies and Mobile
Third-party cookies are the workhorses of PC web measurement, while in mobile their use is problematic. Cookies have very limited capabilities in some mobile browsers, and in apps. Instead, companies use SDKs to track in-app user activity and associate all of those actions to a device advertising ID.
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