It is provided a method of matching pairs of persons. The method includes receiving from the persons personal opinions on other persons, and based on a collaborative filtering algorithm, calculating from the personal opinions a first estimated opinion of a first person on a second person and a second estimated opinion of the second person on the first person. The method also includes matching the two persons in accordance with the estimated opinions and connecting them for a predetermined time duration. The first estimated opinions may be the estimated probability that the first person wants to be matched to the second person. The matching of the two persons is done in accordance with the product of the probabilities. Matching order is determined by a difference between a highest and a second highest product of a person in two different pairs.