What is the importance of Co-Occurrence in SEO factor?
Co-citation refers to the similarity between two websites based on a third party website. It would clearly define the co-relation with the two sites. But co-occurrence is something different from the co-citation. The concept of anchor links are weakening, while Co-occurrence is becoming an important ranking factor.
Co-occurrence is the association of some particular phrases or important keywords of the two sites altogether. The close proximity developed between the two sites is an additional SEO boosting factor.