Google penalizes you for having duplicate content on your website.
You should only have Google index your single posts, pages and categories. Anything else, is duplicate content of the original file.
Only INDEX posts, pages and categories.
Place this code in your header.php file for your template in between <head> and </head>
<?php
if((is_home() && ($paged < 2 )) || is_single() || is_page() || is_category()){
echo ‘<meta name=”robots” content=”index,follow” />’;
} else {
echo ‘<meta name=”robots” content=”noindex,follow” />’;}
?>
HTACCESS Method.
Place this in your .htaccess file in your root folder of your web host.
User-agent: *
Disallow: /wp-
Disallow: /search
Disallow: /feed
Disallow: /comments/feed
Disallow: /feed/$
Disallow: /*/feed/$
Disallow: /*/feed/rss/$
Disallow: /*/trackback/$
Disallow: /*/*/feed/$
Disallow: /*/*/feed/rss/$
Disallow: /*/*/trackback/$
Disallow: /*/*/*/feed/$
Disallow: /*/*/*/feed/rss/$
Disallow: /*/*/*/trackback/$
Source: How to Make a WordPress Blog Duplicate Content Safe
