A computer-implemented method of providing one or more selected tracking tags to a plurality of domain owner servers for deployment on a plurality of respective websites, the one or more tracking tags being selected from a set of available tracking tags, the method comprising: Storing the set of available tracking tags, each available tracking tag including a purpose parameter describing a use to which data collected by the available tracking tag will be put and a plurality of website IDs identifying the respective websites on which the tag should be deployed; Storing a plurality of user identifiers and a plurality of sets of tag-selection parameters, each user identifier identifying a website user and having an associated set of tag-selection parameters which identity a specific tracking tag and indicate whether a user consent has been obtained for a specific purpose of the specific tag; Receiving, from a domain owner server of the plurality of domain owner servers, a request for deployment of one or more tracking tags on a respective website of the domain owner server, the request including a received user identifier identifying a user accessing the website; Determining whether a user dissent or a user consent exists in the stored sets of tag-selection parameters, wherein if it is determined that no user consent or dissent exists, obtaining the user consent or the user dissent from the user by: Sending a message to the domain owner server requesting consent; and Upon receipt of a response from the server indicating the user consent or the user dissent for a specific purpose of a specific tag, using the specific purpose of the specific tag to modify the associated set of tag-selection parameters which identify the specific tracking tag; For a user identifier corresponding to the received user identifier, comparing the tag-selection parameters for each specific tracking tag to the purpose parameter of each corresponding available tracking tag; Selecting available tracking tags where the purpose parameter of the available tracking tag corresponds to a specific purpose which has an indication of user consent in the corresponding tag-selection parameters; and Transmitting the selected available tracking tags to the domain owner server for deployment on the respective website. Storing the set of available tracking tags, each available tracking tag including a purpose parameter describing a use to which data collected by the available tracking tag will be put and a plurality of website IDs identifying the respective websites on which the tag should be deployed; Storing a plurality of user identifiers and a plurality of sets of tag-selection parameters, each user identifier identifying a website user and having an associated set of tag-selection parameters which identity a specific tracking tag and indicate whether a user consent has been obtained for a specific purpose of the specific tag; Receiving, from a domain owner server of the plurality of domain owner servers, a request for deployment of one or more tracking tags on a respective website of the domain owner server, the request including a received user identifier identifying a user accessing the website; Determining whether a user dissent or a user consent exists in the stored sets of tag-selection parameters, wherein if it is determined that no user consent or dissent exists, obtaining the user consent or the user dissent from the user by: Sending a message to the domain owner server requesting consent; and Upon receipt of a response from the server indicating the user consent or the user dissent for a specific purpose of a specific tag, using the specific purpose of the specific tag to modify the associated set of tag-selection parameters which identify the specific tracking tag; Sending a message to the domain owner server requesting consent; and Upon receipt of a response from the server indicating the user consent or the user dissent for a specific purpose of a specific tag, using the specific purpose of the specific tag to modify the associated set of tag-selection parameters which identify the specific tracking tag; For a user identifier corresponding to the received user identifier, comparing the tag-selection parameters for each specific tracking tag to the purpose parameter of each corresponding available tracking tag; Selecting available tracking tags where the purpose parameter of the available tracking tag corresponds to a specific purpose which has an indication of user consent in the corresponding tag-selection parameters; and Transmitting the selected available tracking tags to the domain owner server for deployment on the respective website.