Much of the talk about the SEO benefits to gathering links centers on inbound links (where people link to you.)  These links are undoubtedly valuable, but there are benefits to linking to articles and content within your site that go beyond search rankings.

Creating links helps search engines find you and the content on your site.  Even those that link to content within your own site are helpful in this matter.  But how else do these links help?

1.  They show the user you spend time and energy on your site.  You don't just slap content up on your site.  You know the content that you have and these links show users that care enough to make sure inter-related topics are connected.

2. Internal links help increase the time people spend on your site.  Offering multiple pages with connected content and linking to it, helps to increase the amount of time a user will stay on your site.

3.  www.ProBlogger.net recommends two great tools that help you with linking.  The first is Yoast's breadcrumb plug-in for Word Press.  This helps you to set up a structure that links your main pages and shows that to the user.  It's the part of a site that shows you how you landed on the page where you are currently located.
SEO Smart Links. This tool helps you to connect to blog content by matching keywords, tags and titles.  Very helpful, especially if your blog is a couple of years old.  It's nearly impossible to remember all that you've written.

4.  A final reminder.  Don't overdo it.  Google has said that too much linking is a problem as well.  So be careful not to overdo it, as then you will achieve the exact opposite of what you want to do.

Bottom line…internal linking enhances the user experience and after all, that's what it's all about right?