Dupe Content explained

Duplicate content is a plague for webmasters.  Scrapers parrot our own content right back at us, and years ago they used to sometimes rank higher than we did!  Webmasters have a ton of questions about this stuff.  SEOMoz has done a good job laying it all out in this rather amusingly illustrated guide to dupe content.

Key points:

• Google puts what it believes to be the “dupe” content into supplemental pages so it won’t rank as high as the original.
• What if a scraper is stealing your content?  As long as they’re ranking below you, don’t worry – it’s just not worth it.  But if you’re new and/or they’re a powerful site, this could squeeze you out.  Fortunately, you have some options: “One option is to file a DMCA infringement request with Google, with Yahoo!, and with MSN. The other is to file legal suit (or threaten such) against the website in question.”
• Having some duplicate content shouldn’t hurt your domain.  If you have a lot of it, however, you may want to consider putting meta tags on the dupe pages to keep robots from following.  That way, you avoid potential penalties.