Internal Duplicate content in WordPress is a major problem to fix. Many of high ranking blogs loosing their rank because Google penalizing them for duplicate content. There are many factors by which your WP blog / website is generating duplicate content and may be you are not aware of it. So here I am going to tell you “How to avoid duplicate content with All in One SEO WP Plugin” If you are using All in One SEO WordPress Plugin.
All in One SEO General Settings
So Let’s start with the All in One SEO general settings by using canonical urls. Your every WordPress post or page can be accessed by 2-3 different URLs. If you are indexing all these ULRs means you are generating high volume of duplicate content. The solution to avoid these type of duplicate link is “Canonical URL“. So Here tick on the Canonical URLs & No Pagination for Canonical URLs. These options will help you to provide a single URL for the search engine of a post.

All in One SEO Noindex Settings:
Now come the Noindex Settings. Here you will see different Noindex options. There are some default Noindex, NoFollow, NOODP & NOYDIR options. You can use them according to your choice but generally all these option left unchecked because most of us do not want to apply these settings to all our elements.

As I am Using a Plugin a display DFP ads and I do not want to index them anywhere and I also don’t want to index the Grid Elements. So Here I checked the option of Noindex and noFollow. You can use them according to your usage of custom post type.

So let’s come to the next section and this one is the most important section as here we will noIndex some elements that are the main factor of duplicate content.

Let’s Discuss one by one all these options of All in One SEO:
Use NoIndex for Category – If you are using same content in many category in high volume. For example you are displaying 10 post per page in category and published 10 new post but selected 2-3 category for these all 10 recent posts. Then there may be a chance to generate duplicate content. And if you are repeating this situation then I would like to suggest you to use Noindex for Category otherwise you can left it blank.
Use NoIndex for Date Archives: Indexing date Archives may be a way to generate the duplicate content. So I would like to suggest you to avoid indexing it. You can use default noIndex and noFollow for date archives.
Use NoIndex for Author Archives: If you are running a single author blog and indexing the author archives means you are generating a large number of duplicate content. So use NoIndex for Author Archives immediately. But If your website or blog is multi author then you can index author archives.
Use noIndex for Tag Archives: Tag plays very important role in sorting of posts in your website. But using too many tags may and do not using them again to other post then it can cause duplicate content. So it is advisable to re use the tags and keep them indexed.
Use noIndex for Search Page: Some times search page generates duplicate content. So use noIndex for it.
Use noIndex for 404 Page: Keep this page indexed.
Use noIndex for Paginated pages / posts: If you are giving pagination to your post like www.example.com/post/1, www.example.com/post/2, www.example.com/post/3 and want to index all the pages then you can unchecked it. Other wise you can use noIndex for paginated pages / posts.

So these are the ways to configure the All in One SEO to avoid internal duplicate content in WordPress blog. In next post we will discuss about how to avoid duplicate content by using Google Webmaster Tool.