The policy on biographies of living persons sets out that "Self-published books, zines, websites, and blogs should never be used as a source for material about a living person that is controversial, or derogatory, or impossible to verify otherwise,  unless written or published by the subject of the article (see below)". The policy on external links indicates that these should only be used to add "meaningful, relevant content that is not suitable for inclusion in an article for reasons unrelated to their reliability". On that same policy, blogs are specifically mentioned as links to be avoided "except those written by a recognized authority" (which, in this context, BLP specifies is the subject of the article). The policy on verifiability indicates that "Anyone can create a website or pay to have a book published, then claim to be an expert in a certain field. For that reason, self-published books, personal websites, and blogs are largely not acceptable as sources".