Consistent　description　and　representation　method　of　user　interests　are　required　for　personalized　Web　applications.　In　this　paper,　we　provide　a　formal　definition　and　the　＇e-foaf:interest＇　vocabulary　for　describing　user　interests　based　on　RDF/OWL　and　the　FOAF　vocabulary.　As　an　application,　under　the　framework　of　unifying　search　and　reasoning　(ReaSearch),　we　proposed　interests-based　unification　of　search　and　reasoning　(I-ReaSearch)　to　solve　the　personalization　and　scalability　requirements　for　Web-scale　data　processing.　We　illustrate　how　user　interests　can　be　used　to　refine　literature　search　on　the　Web.　Evaluation　from　the　scalability　point　of　view　shows　that　the　proposed　method　provides　a　practical　way　to　Web-scale　problem　solving.　©　2010　Springer-Verlag.