Some unscrupulous websites manage to get a more favourable ranking by basically “scraping” content from other websites. What happens is this:
Google “crawl” sites with their virtual robots at regular intervals, depending on certain factors including how often the site updates its content and the sites popularity. Depending on the timing, the site that lifts the content may get crawled first and can be indexed as “content originator”. To make matters worse when the search engines subsequently crawl the site that actually created the content they can be punished for having duplicated their own content!
The ingenious solution to this is to register ownership of your content by establishing Google “Authorship”. This is done by linking your Google Plus account to your website clearly indicating that you have created the content. More detailed information on Google Authorship can be found here.
Update Sep 2014 – Unfortunately Google in its wisdom has dropped Authorship because the little profile photos was attracting more attention than their ads! I’m just leaving here for posterity. Thanks Google for that curved ball!