Google organizes the worlds information, according to its Mission Statement. One of the biggest problems for Google is dealing with multiple sources that cite the exact same information, or even what they would consider "very close to the same." This area of Google's indexing algorithm specifically deals with the issue now commonly known as duplicate content. As we can tell by research, "duplicate content" is a little misleading since it refers to "nearly duplicate" as well. We recently covered this subject in specific regards to Article Syndication.
A thread at Search Engine Roundtable Forums brings up a nice real-life example of how Google sometimes omits certain pages from the default results due to being considered duplicate content. The member suggests that the solution in this case (the example discusses SER Forum pages indexed) is
to reduce unnecessary code on page
Barry wonders when "Google will "get it right..." However no further opinions have been added. Please join the Search Engine Roundtable Forum topic and give your thoughts or relate your experiences on the subject of Google unique content determination. Real "live" case studies usually lead to nice concrete discussion.