Some people say that Copyscape is the best way to check if your content was copied by someone else or the article you are intended to by has been copied and used by the guy you hired. Others say that using it is a mistake and it's not so buletproof the fans consider it to be. For the moment is one of the most popular plagiarism checkers and it's taken into consideration by so many people you have to take also in consideration in order to make yourself a reputation as a blogger and a content writer.
The problem with Copyscape is that uses an algorithm and the search engines use different algorithms. Nobody would say exactly what statistical search algorithm uses or what are its changes during time time, but it seems fair to consider that using Copyscape along with the search engines will increase the chances to get a similar or identical content.
If you paid attention to the last pharagraph, I used the expression "statistical search algorithm". The keyword is "statistical": there is so much content on the internet there are some chances (in some areas of activity there are big chances) that someone else used the same words as you (or even yourself in a different period of time) to describe the same situation, event, product or service. The Copyscape statistical search algorithm is based on certain unique phrases throughout the content of an article, so if you reuse only a part of a source article Copyscape may pass the result as valid.
So, no matter what, be unique. If you get your ideas from another (blogers or competition) don't use their content too! The internet is huge and it's increasing in content every day. For the moment it's free, but there are trends to protect the copywrited online material in detriment of personal freedom (remember SOPA and ACTA and the protests against them). There is no way to know what will happen in the future and how will be the laws about the plagiarism - the best way to protect yourself starting now. Be (express) yourself when you write.
Passing your articles on Copyscape can increase their credibility, but always remember that no one can copy forever others' ideas. If you don't write yourself your content you can only damage your reputation in the future.
