  Most news recommender systems try to identify users' interests and news'
attributes and use them to obtain recommendations. Here we propose an adaptive
model which combines similarities in users' rating patterns with epidemic-like
spreading of news on an evolving network. We study the model by computer
agent-based simulations, measure its performance and discuss its robustness
against bias and malicious behavior. Subject to the approval fraction of news
recommended, the proposed model outperforms the widely adopted recommendation
of news according to their absolute or relative popularity. This model provides
a general social mechanism for recommender systems and may find its
applications also in other types of recommendation.
