Abstract
Although, the growing number of Internet users who can play a prominent role in building collaborative groupware systems, the ability to find helpers (tutors or other learners) is still a challenging and important problem. Helpers could have a lot of useful information about courses to be taught, however, many learners fail to understand their presentations. We suggest a new filtering framework, called a pyramid collaborative filtering model, to trickle the number of helpers down to just one. The proposed pyramid has four levels. Moving from one level to another depends on three filtering techniques: domain model filtering; user model filtering; and credibility model filtering. Our experiments show that this method greatly improves filtering effectiveness.