This document discusses James Porter's concept of intertextuality and discourse communities. Some key points: - Intertextuality challenges the idea of the writer as a lone genius and instead sees writing as constrained and situated within various discourses and traditions. - Writers are influenced by 11 different types of texts and act as "collectors of fragments" when piecing together their own writing. - Discourse communities are groups bound by common interests that regulate acceptable communication within the group. Writers belong to multiple discourse communities that further influence their work. - No text is truly original or the product of a single author, as all writing borrows and builds on previous texts through intertextual references and traditions.