
To understand one reason why it would be useful, let’s examine how page rank is typically assigned to a website. Keep in mind this is an oversimplification of how Google actually works, but it’s useful as a model. Let’s say your site has been assigned a page rank of 5, that means it has 5 points to distribute to all its pages. So if there are 5 links on the home page each link would get 1 point. Now let’s say that page also has 5 links, each of those links would get 1/5 of a 1 point. So what’s the takeaway from this? That the more clicks it takes to get to a given page, the less value Google and the other search engines assign to it.
So if your WordPress blog uses the default, out of the box pagination; your older posts are going to be considered less valuable, because the user and the search engines have to “click” on more links to get to them. This might be fine for some blogs that are more current events focused, but many blogs have good “evergreen” posts, that even written some time ago are still valuable.

For example, let’s say blog post #7 was a popular post, ranked well for it’s keywords etc. But I’ve written 6 blogs posts since then, and now it has moved off the home page and even off the first page of its category page. Because it now takes three clicks (see above) to get to post #7, the post gets less “SEO juice” given to it by the search engines.

The WP PageNavi plug aims to solve this by leveling the playing field for your older posts. As you can see, it now takes two clicks to get to the blog post page for post #7. Up to this point I haven’t bothered with installing the plugin – yes, the benefits are clear – but how much difference will it make really? So now, especially since I do treat this blog as a sandbox to try out optimization techniques, I’ve finally installed it. I’m hoping it will help my older posts, but the proof will be if I see an increase of traffic to older posts.

Hi Kathy, so how is the result of your pagenavi test?
I just install it today base on SEO advice and anxious to see the result
What is your advice thanks Kathy for the informations
To measure the impact you can do the following:
1. Measure the link depth of your site and find a few pages that are many clicks away from the home page.
2. Identify their current ranking. This will require some digging around in GA and GWMT if you don’t have access to 3rd tools that measure ranking.
3. Install WP-pagenavi and first see what the improvement for link depth is.
4. Then after Google has crawled the pages (use cache: and info: directives) see if the ranking has improved.
You can also use traffic as a measurement.
Dear Kathy,
Thank you for your sharing but could you inform alternative plugins for page navi ?
Hmm, I don’t have any alternatives to suggest. Do you have one I should take a look at?