— Eric Enge, Stephan Spencer, Jessie Stricchiola, and Rand FishkinThe easiest way to do this is to take unique strings from each of the major content pages on the site and search on them in Google. Make sure you enclose the string inside double quotes (e.g., “a phrase from your website that you are using to check for duplicate content”) so that Google will search for that exact string.
Replicated under Fair Use from The Art of SEO (Theory in Practice) by Eric Enge, Stephan Spencer, Jessie Stricchiola, and Rand Fishkin.