12. The method of claim 11 , wherein the common-interest strength is also calculated using the correlation coefficient of the first user and the second user.
11. The method of claim 10 , further comprising: calculating a correlation coefficient based on: an average interest score of the plurality of common-interest information topics from the first user, a second average interest score of the plurality of common-interest information topics from the second user, the interest score of each interest of the plurality of common-interest information topics from the first user, and the second interest score of each interest of the plurality of common-interest information topics from the second user.