A web server and a shared caching server are described for serving dynamic content to users of at least two different types, where the different types of users receive different versions of the dynamic content. A version of the dynamic content includes a validation header, such as an ETag, that stores information indicative of the currency of the dynamic content and information indicative of a user type for which the version of the dynamic content is intended. In response to a user request for the dynamic content, the shared caching server sends a validation request to the web server with the validation header information. The web server determines, based on the user type of the requestor and/or on the currency of the cached dynamic content whether to instruct the shared caching server to send the cached content or to send updated content for serving to the user.