internal links are links that point to another page on the same domain (same website). internal links are important for all websites, not just sites build with WordPress.
Besides making the navigation easier for users, internal links have two other great benefits as well.
- Spreading the link juice
- Make the website more crawler friendly
What does spreading the link juice mean?
If you are a website owner, you probably might have noticed that some of your pages are ranking better than others. While there might be multiple reasons behind this, popularity of the page is naturally the main reason. For example popular and good articles get more shares and therefore there are more pages linking to your article. It has more backlinks. How much value the backlink has, depends on the authority that is linking to your content.
By adding an internal link to this article that has good backlinks, you will transfer more juice to other pages of your website. What you are basically doing, is spreading the power to other pages to make your whole website stronger.
With WordPress, it is usually your posts that may or may not get attention (same goes for other blogs as well). While articles get power as they are being shared over the internet, it is up to you to spread the power to other pages and posts. Include few internal links on your post to make sure that the juice flows through your site.
Making the site more crawler friendly
When internal linking is done properly, the website is more crawler friendly. Googlebot and other crawlers can understand your website better. As a rule of thumb, your page should be like a connected chain (Fig1). This means that when the crawler bot arrives to your page A, it should be able to navigate through the whole website with internal links. This does not mean that each page should have links to all of your pages. However through internal links the bot should be able to eventually crawl the entire website.
More WordPress SEO
Goodreads on internal linking: