A method in a client-server network, comprising - rendering, by a client , a first webpage for registering a new user, - receiving, at the client , data including personal information and/or indicative of user identity information filled into a second webpage, - submitting the data to a server , - creating, by the server , a user account, - assigning, by the server , a user identification in response to receiving the data, - passing the user identification as a parameter to a third webpage which the user is redirected to, - loading the third webpage that shows a description of tracking and provides a user input in the client for the user to agree to the tracking, - if the user agrees, loading a fourth webpage passing the user identification as a parameter, wherein, on the fourth webpage, the user is informed that an entity tag is set on a browser, - generating, in the client , a setting request for setting the entity tag in the server , - receiving the setting request in the server , - generating the entity tag in the server , the generating comprising providing the user identification in the server and including the user identification in the entity tag, - generating a response to the setting request in the server , the response comprising the entity tag provided in an entity tag field of the response, - receiving the response in the client , - caching the entity tag in the client , - generating, in the client , a content request for retrieval of content provided in a resource in the client-server network and identified by a resource locator, the generating comprising including the resource locator and the entity tag in the content request, and - transmitting the content request from the client to the resource. - rendering, by a client , a first webpage for registering a new user, - receiving, at the client , data including personal information and/or indicative of user identity information filled into a second webpage, - submitting the data to a server , - creating, by the server , a user account, - assigning, by the server , a user identification in response to receiving the data, - passing the user identification as a parameter to a third webpage which the user is redirected to, - loading the third webpage that shows a description of tracking and provides a user input in the client for the user to agree to the tracking, - if the user agrees, loading a fourth webpage passing the user identification as a parameter, wherein, on the fourth webpage, the user is informed that an entity tag is set on a browser, - generating, in the client , a setting request for setting the entity tag in the server , - receiving the setting request in the server , - generating the entity tag in the server , the generating comprising providing the user identification in the server and including the user identification in the entity tag, - generating a response to the setting request in the server , the response comprising the entity tag provided in an entity tag field of the response, - receiving the response in the client , - caching the entity tag in the client , - generating, in the client , a content request for retrieval of content provided in a resource in the client-server network and identified by a resource locator, the generating comprising including the resource locator and the entity tag in the content request, and - transmitting the content request from the client to the resource. <EOS>