Do you know how major search engines respond to a search query? They send out their robots (or spiders if you prefer) 24/7. The spiders index every web page they find (note page not site) for the content they have on them. If the content is unique, the spiders index every time they visit, and file your page as relevant to your keyword or phrase while at the same time noting that your page always seems to have new information pertinent to that phrase or subject on hand.
Thats why unique content is the key to ranking well in search engines. Unique content fulfills the oldest criterion of all for good SERPs listing: that the information you are holding is not just relevant, but current. The Internet is obsessed with newness and search engines algorithms are designed to reflect that. So if you want to rank high on a consistent basis you need to be sure that your score for continually updated information is as good as your score for the relevance of that information.
Your content has to be unique as well as fresh. Google and the other search engines know if there are multiple copies of your article or your page content out there on the web. Be sure you use the right keywords and phrases to link your fresh content with the areas you are optimising for: and make sure also that the actual text that contains those key words and phrases is not duplicated endlessly otherwise your ranking will fall quickly.
Benefits of using unique content on your website
No one knows the exact algorithm that Google uses to determine whether your content is unique or not. What we do know is that genuinely unique content, which does not appear elsewhere on the internet, is obviously rewarded in the SERPs because sites that use unique content rather than scraping and altering, or continually putting out the same kind of stuff, are climbing the relevant ranks pages rapidly.
There are ways to trick search engines into thinking that your content is unique like pulling off RSS feeds and incorporating blogs in your own pages but the Google engine is clearly able to distinguish when you are doing this. The bottom line unique on page content is becoming more and more influential in determining how often and how well your pages are indexed by the search engine spiders.