Ambiguities with respect to a user topic interest may be resolved so that useful topic-relevant ads can be presented. Such ambiguities may be resolved by monitoring user behavior, determining a user topic interest (e.g., from a plurality of different candidate topics) based on the monitored behavior,...http://www.google.com.hk/patents/US8090706?utm_source=gb-gplus-share專利 US8090706 - Rendering advertisements with documents having one or more topics using user topic interest information
