We have tested that the use of keywords in the internal link anchor text is highly effective in rankings and a particular element that separates top ranking sites to the bottom ones. Basically how we set up this experiment is very simple.

Methodology:
1. We compare two pages that ranks in Google for a particular key phrase. One page ranks in Position 1 and the other page ranks Position 100.
2. We take a random sample of around 5 competitive keywords.
3. We take a random sample of 6 pages within the domain. Then we examined the anchor text used to point to the ranking page of that domain for the tested key phrase.
4. We take the % ( number of pages containing the targeted keywords in the internal links pointing to the ranking page/ 6)
5. We average all the samples and compare the results.

Results:

Based on the actual result, there is a large difference between the two. Top sites makes the effective use of keywords in the internal link anchor text while those sites in the bottom just ignore this one.

The reason is that Google uses links to assess relevant pages, so this means that internal link popularity is indeed very helpful in finding relevant pages. The higher the % or the quantity of those pages that are pointing to the target page, the higher will be the relevance or importance value. Using keywords in internal links conveys message to Google of what you mean by that page, thus helping Google to understand the site better and will rank better too.

But this cannot be fake, abnormal use of this one involves creation of “doorway pages “which is a violation of Google quality guidelines and highly discourage. I have seen a lot of webmasters making the use of keywords in the internal link anchor text and point it to doorway pages. It will not rank and will just penalize a site.

This means that if you use the power of the keywords in the internal link anchor text, you should be having a relevant and substantial content too to support the validity of those links.

Overall Recommendation based on this study:

1. Every time you need a page to rank in Google, have all pages in your site link to it using the optimized keywords in the anchor text.
2. The page that you need to rank should contain substantial and relevant content to the optimized keyword. This means the content there should contain at least the exact match on the page (required by Google) and should be well-written.