Hello I have this site that features books & reviews, and my visitors can comment their own opinions about the books. Now the listing is quite big, covering over 2000 books with reviews. Now the problem is, that i have these categories for the books: By genre: Literature Sports Action etc... By country: China Japan etc... By Author: John smith lauren learningday etc.. Now the problem is that i have unique pages for same book in each category that has the same information and review, but the comments and advertisement changes different in each category, also the pages have different name: Example: By author: John-Smith-Eating-Fat-book.php By country Sweden-Eating-Fat-Book.php So how does google see this? Will google alarm bells start to ring, or does it see it, just as it is. The thing is that i wan\\\'t this structure for personal reasons and for advertisement reasons, but i dont want to hurt my rankings. Is this black hat in googles opinion? or can i do it? SkyDesign
Its better for each book to have the 1 unique URL. Also its a bit silly having the comments on a book different and spread across multiple pages. If i found the book by Author i wouldnt get to read the comments on that same book on the Category or whatever other version which could be important to me and prompt me to buy it. But if you insist in doing it that way, Google will see the different versions and count them as duplicate pages and only one version will rank well. It wont "harm" you as such but it isnt ideal. One page, one book and one set of comments is how i would do it.
Google will only count them as duplicate pages if the content is the same. It's like posting this reply several times over different threads. Personally though, I'd group the books by genre, and include a site search feature that would let people search for books by author, country of publication, genre (or subject) and title.
Pick one page that you want Google to rank and refer the others to it using the canonical meta tag. It's a very new tag created for situations just like this. The other major engines have pledged to support it as well