1. A system configured to generate content comparison reports, the system comprising: one or more physical computer processors configured by machine-readable instructions that cause the one or more physical computer processors to: access product pages through which products are offered for sale on one or more sites via a network, the product pages including: a first product page through which a product is offered for sale on a first site, and a second product page through which the product is offered for sale on a second site; determine similarity of content between product pages for the same or related products, such that a similarity of content is determined between the first product page and second product page; generate content comparison reports including results of the determination of similarity between product pages for the same or related products, such that a first content comparison report is generated that reflects the determined similarity of content between the first product page and the second product page; generate recommendations of changes to be made to content included in one or more product pages in a set of product pages to reduce similarity between the content included in individual ones of the product pages in the set of product pages such that implementation of the recommendations will cause the reduction in similarity between the product pages, the reduction in similarity being indicated by a subsequent determination of similarity of content between the product pages, the recommendations including a first recommendation of changes to be made to content in the first product page that will cause the similarity between the content in first product page and the content in the second product page to be reduced, the reduction in similarity between the first product page and the second product page being indicated by a subsequent determination of similarity of content between the first product page and second product page.