Internal linking can be a great way to increase traffic to specific pages on your site, but be careful how your implement your strategy. You could do more harm than good.
The Google algorithm is mathematical and recognizes patterns. Once a pattern is detected chances are your site is at risk for some type of penalty. Whether you have duplicated content or thousands of links, internal or external, that all have the same anchor text, the Google algorithm will eventually find you and penalize your site’s traffic.
Recently I was counseled by an outsourced SEO firm to put an XML file in my site that automatically detects keywords on a new article and links that article to a specified page. The problem – there is a new article every day, and those new articles mostly all have that keyword in them. Admittedly, I listened to their council. Now I have to reverse my wrong doing in fear that my site is at risk of the Google Over-Optimization Penalty. Rand Fishkin, from SEOMOZ goes into more detail about this penalty:
How to Make Natural Internal Links
Instead of creating an automated system to link pages within your site, just link to articles when they seem appropriate. If you outsource your content with freelancers, instruct them to quote two sources in every article. Humans are inconsistent and there will never be a pattern for the algorithms to penalize. Quick fixes and automated systems can always be detected by a machine.