A month ago, SEO Black Hat had an experiment about the effect of on-site intra-linking to SEO. Particularly the experiment is about click distance and how it could bring more or less traffic from search engines.

What is Click Distance?

First of all, click distance is the number of clicks it takes to reach to a web page from the homepage of the site.

If a site was structured or organized like directories, then access to example.com/page1.html should be one click away, while example.org/category/subcategory/subsubcategory/page2.html is 4 clicks away from the homepage.

Search engines value a page with less Click Distance score better than one with higher score. In some search engines, the deep of the page and directory structure also matters.

What Was the Experiment

The experiment is about both SEO and usability. First, he deleted all the Category links from the sidebar and put a link to every post ever written, using the title of the posts as the anchor texts.

The site had gone supplemental after 182 results prior to the experiment.

Finally, he also got rid of the Google Sitemaps file — both sitemap.xml and sitemap.txt from the server and deleted the sitemap from Google Webmaster Tools.

The Result

For the month of September 2006, SEO Black Hat had these search referral numbers:
Google 24889
Yahoo 1047
MSN 503
Ask Jeeves 91
Google Images 82

In August, 2006 with search referrals of
14258 - Google
1603 - MSN
1266- Yahoo
41 - Ask Jeeves
19 - Google Images

and these numbers in July
11995 - Google
1145 - MSN
828 - Yahoo
514 - Google Images
34 - Ask Jeeves

There was a 74% climb in the number of Google search referrals. MSN switched to Live, Yahoo! was down slightly and Ask Jeeves up slightly.

For supplemental pages, now the blog does not go supplemental until 554 results.

Current Hypotheses

What caused the raise in search engine referrals? We can be sure that during the months the site also gained backlinks from other blogs and sites. The site also got a bunch of referrals from Internet trends search like “Fortuny” and “lonelygirl15″.

But those aside, there are two factors that he thought had contributed to the traffic:

1. Stickiness and number of visits — due to the private SEO Black hat forums.
2. Click distance

Take Away Lessons

If there is only one thing I could learn from the experiment, it is to structure the blog so that you always display the most recent posts on the homepage, and perhaps also related posts on all blog pages.

Internal linking is not only important but also could immediately increase readership. Link to your old posts so visitors are more likely to find them.

Make your flagship posts easy to access; as few clicks from the homepage as possible.

Last but not least, create a community where people will continually come back for more and stay longer.

[SEO Black Hat]