E.Dieter Martin: Your other choice is to log the 404's from external and keep track of the referring URL's. A couple of WordPress security and SEO plugins will do that. Feeding the logs into a spreadsheet and careful massage of the data will help as well.
Tony McCreath: If you Google <b>gwt backlink checker</b> you may find a tool that does it for you ;-)
Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 00:09:15 into the YouTube video:
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