The content based filtering is domain sensitive and collaborative filtering is domain free.
Collaborative filtering suffers from cold start problem as we might not have the sample data to initially start off with.
User centered collaborative filtering:
Pearson correlation coefficient between ratings for active user and another user is given as
Ca,u = Covar(ra,ru)/StdDevia(ra)/ StdDevia(ru)
Its similar to dotproduct formula
Srividya
