The widespread adoption of large-scale decentralized peer-to-peer (P2P) systems imposes huge challenges on distributed search and routing. Decentralized and unstructured P2P networks are very attractive because they require neither centralized directories, nor precise control over network topology or data placement. However their search mechanisms are extremely unscalable, generating large loads on the network participants. In this paper, to address this major limitation, we propose and evaluate the adoption of an innovative algorithm for routing user queries. The proposed approach aims at dynamically adapting the network topology to peer interests, on the basis of query interactions among users. Preliminaries evaluations show that the approach is able to dynamically group peer nodes in clusters containing peers with shared interests and organized into a small world topology.