Those new to SEO might not know that Google does not place all of the pages it spiders into the main index. Known to some as Google Hell, the Google Supplemental Index is where Google places pages that it considers less important. This lack of importance can be due to any number of factors - duplicate content, lack of Page Rank, orphaned pages, etc.

In a nutshell, pages in the Supplemental Index are in a kind of limbo and only show up in the SERPs (search engine results pages) when there is absolutely nothing for the search query in the main index.

One theory of why Google came up with such a thing has to do with the sheer magnitude of spidering and indexing involved. To sift and sort the world’s data, lots of servers are needed. The theory is that Google decided to separate what it considered the best into the main index and dump the rest into a secondary index - just in case.

Google, of course, has a different spin on what the Supplemental Index is. Google’s Matt Cutts, the closest thing to a search engine engineer rock star on the planet, puts it this way:

“Having urls in the supplemental results doesn’t mean that you have some sort of penalty at all; the main determinant of whether a url is in our main web index or in the supplemental index is PageRank.”

But, ask any site owner or webmaster who suddenly finds their site pages in the Supplemental Index and they will see it as a penalty, the equal of the previously mentioned Google Hell.

How do you even know if you have pages suffering damnation in the fiery pit? Just type the following into the Google search box, changing yoursite to whatever your domain is, of course:

site:www.yoursite.com *** -sjpked

I can already hear all of the I Love Lucy “eeeeewwwwwwwws” and picture the Lucille Ball-like grimaces coming from the other side of my monitor now!

Lucy! You got some ’splaining to do!

If your site is small, your task should not be that difficult. If what Matt says is true, you will need to boost the Page Rank for the pages you find in the Supplemental Index by getting some quality external links pointed at them.

If you have a huge, dynamic site with thousands of pages built off of the same template, your task will be more difficult. Chances are your pages have very similar content. As I mentioned in my S E O 101 post, there is evidence that having a unique TITLE and Meta description tag on each page will help keep pages out of Google’s Supplemental Index. And, you need to have unique text on the pages. So, in addition to boosting quality backlinks to the pages, you’ll have your work cut out for you creating content.

There just is no “Get Out of Jail Free” card for the Supplemental Index. The only way to achieve good ranking and increase your chances of staying out of Google Hell, is to create good, quality content and combine it with good, quality linking.

And, give it some time.