Can a website have duplicate content within a website ? Yes ! It can.
If you are displaying products on one of your webpage in alphabetical order.
Say in another page you are displaying the Products in Ascending or descending order of Cost ?
Basically both the pages have same content and only way they are different is the way they are arranged based on some criteria.
Now in this case Google / Bing / Yahoo or any search engine will not know… 1) Which Page version(s) to include/exclude from their index. 2) Whether to direct the link metrics (trust, authority, anchor text, link juice, etc.) to one page, or keep it separated between multiple page version. 3) Which version(s) to rank for query results.
The Tag is as follows..
<link rel="canonical" href="http://www.sunil.ca/blogs" />
Adding this Tag in head section of a duplicate page will inform the search engine to rank
Though we can have all duplicate content. We can also track visitors on all duplicate pages. This Tag just lets Search engines know that the page in the href is original page and should rank this page passing all link juice/ trust / authority.
If you have any questions pleas feel free to contact me. By Sunil Datar Google+