A system, computer-readable storage medium storing at least one program, and a computer-implemented method for confirming authorship of documents is presented. A first document hosted on a first website of a first domain is accessed, the first document being linked to a second document through at least one link, and a respective link including a first predefined authorship attribute asserting authorship of a respective document including the respective link by a respective entity associated with a respective target document of the respective link. Authorship of the first document by an entity associated with the second document is conditionally confirmed when the second document includes a second link to the first website of the first domain, the second link including a second predefined authorship attribute indicating that the entity associated with the second document is an author of or contributor to content at the first website of the first domain.