to store and track visitor journeys through the site and classifies them into groups.

to store and track visits across websites.

to store number of service requests.

to store and count pageviews.

to Provide parameters to URLs to identify the campaigns that refer traffic.

to Provide parameters to URLs to identify the campaigns that refer traffic.

Thrown when a redirect experiment is running. Stores the experiment ID, variation ID, and referral source to the redirected page.

Retains the last query parameter utm_campaign.

Used for campaigns linked to Google Ads Criteria IDs.

Used for campaigns associated with Google Ads ad group IDs.

Used for campaigns linked to Google Ads Campaign IDs.

Used for campaigns that are linked to Google Ads customer IDs.

Determines when the experiment in which the user participated expires.

Determines if the user took part in the experiment.

Stores data about a visitor level custom variable. Thrown when a developer uses the _setCustomVar method with a visitor-level custom variable. Also used by the _setVar method, which is no longer supported. Updated every time data is sent to Google Analytics.

Stores information about the source of traffic or campaign, allowing you to understand where the user came to the site from. Generated when the library is run and updated every time data is submitted to Google Analytics.

Not used in ga.js. Installed for interoperability with urchin.js. Previously worked in conjunction with the __utmb cookie to determine whether a user should start a new session or visit.

Used to define new sessions / visits. Thrown when the JavaScript library is executed if there are no existing __utmb cookies. Updated every time data is sent to Google Analytics.

Limits the frequency of requests.

Allows you to distinguish between users and sessions. Thrown when the JavaScript library is executed, if there are no existing __utma cookies. Updated every time data is sent to Google Analytics.

Contains a token that can be used to get the Client-ID from the AMP service. Other possible values: disabling the function, active request, or an error in obtaining the Client-ID from the AMP service.

Allows you to differentiate between users.

to provide ad delivery or retargeting.

Cookie for Pinterest functionality

is identical to _pin_unauth, but as a third party cookie.

is a first party cookie which groups actions for users who cannot be identified by Pinterest.

is placed by the Pinterest tag when a match is identified when no cookies are present, such as Enhanced Match.

is placed by the JavaScript tag based on information sent from Pinterest with promoted traffic to help identify the user.

_pinterest_ct and _pinterest_ct_rt are identical. They contain a user ID and the timestamp at which the cookie was created.

_pinterest_ct and _pinterest_ct_rt are identical. They contain a user ID and the timestamp at which the cookie was created.

is the Pinterest login cookie. It contains user ID(s), authentication token(s) and timestamps. If the person is logged out, authentication tokens are deleted but we leave the cookie present. We use the logged out user ID(s) to optimize the person’s experience and measurement.

to store account details.

to store and track if the browser tab is active.

to store browser details.

to provide fraud prevention.

to store a unique user ID.

to provide fraud prevention.

to store and track visits across websites.

to Store logged in users.

to provide ad delivery or retargeting.

to read screen resolution.

to store a unique session ID.

to store account details.

to store last visit.

to store user preferences

Google Analytics lets you measure your advertising ROI as well as track your Flash, video, and social networking sites and applications

Google AdSense allows websites to earn money by using a Google display tool on the website to host third-party ads that are relevant to their audience.

The Pinterest tag allows website owners to track actions people take on their website after viewing a Promoted Pin.

The Facebook pixel is a piece of code that collects data that helps to track conversions from Facebook ads, optimize ads, build targeted audiences for future ads and remarket to people who have already taken some kind of action on the website.