Automatic adaptation of the environment to user preferences results in personalized ambients that fulfill user interaction requirements in a more suitable way. However, the problem of environment adaptation has been traditionally solved via ad-hoc context-specific solutions. In this paper we present the WebProfiles model, a negotiation mechanism for Ubiquitous Computing, based on Web technology extensions, that enables user preferences awareness capability in surrounding devices and services, so that the environment meets the user and knows him as if specifically designed for that purpose.