title: Finding similar/related texts algorithms
body: <p>I searched a lot in stackoverflow and Google but I didn't find the best answer for this.
  Actually, I'm going to develop a news reader system that crawl and collect news from web (with a crawler) and then, I want to find similar or related news in websites (In order to prevent showing duplicated news in website)</p>
  
  <p>I think the best live example for that is Google News, it collect news from web and then categorize and find related news and articles. This is what I want to do.</p>
  
  <p>What's the best algorithm for doing this?</p>