I was wondering the following thing: Most free forum software, like phpBB have a build-in Help page. Everything on the forum is explained there. But isn't this considered Duplicated content? I think 99% leaves the help content for what it is, because it takes to much time to write something for their own..
Duplicate content really only matters for the pages you want listed in search results. Privacy policy and faqs do not matter to most sites to be listed in google. I know why you asked question but it only applies for the page not the whole site.
To conserve link equity and to send Pagerank to content that actually counts, i'd either "Nofollow" the links to pages like faq.php, search.php, login.php, viewonline.php or even block them with Robots.txt Another "big" tip with phpBB, block register.php with Robots.txt as it will help prevent scripts harvesting forums sign-ups to spam as well as save some link juice, because honestly how many visitors does your register.php bring in? Also if your forum platform has a calendar.php block it, generally it's 1,000s of pages of nothing besides maybe a birthday or two.