This pages have the same or almost the same content:
- www.site.com/?page_id=7 - canonical page;
- www.site.com/?page_id=7&print=1 - print version of the page;
- www.site.com/?page_id=7&page_comments=2 - version of the page with second comments page;
- www.site.com/?page_id=7&hide_comments=1 - version of the page without comments;
If you want to avoid search engines (like Google) scan duplicate content and showing in search results only original content you may add to duplicate pages this code into head section:
<head> <link rel="canonical" href="http://www.example.com/?page_id=7" /> </head>