* Google Trust Problems -
There is some debate about this, but there does appear to be a link between loss of Google Trust (or low trust) and Supplemental pages. Websites which develop Google Trust issues or have low trust due to the fact they are new, seem to be more badly affected by Supplemental results than older, more trusted sites with more backlinks from trusted domains.

Google Trust can be lost by linking out to bad neighbourhoods and link farms, or by extensively using reciprocal link directories with 'free-for-all linking' - a strategy which used to improve organic search engine ranking a few years ago, but now has a negative effect, particularly in Google. A website which exists solely on reciprocal links, with few one way links is more likely to suffer loss of Google trust and get more of its page in the Supplemental results, than sites which have attracted quality one way links as an indicator of quality.

The definition of Google Trust -
A complex measurement of website quality and web popularity. It is loosely based on how many backlinks a website has from authority (hub) sites in related field/s.
The definition of Google Trusted sites -

well established websites which often have top 10 Google organic ranking for competitive terms and an established following, being established leaders in their field. For links from trusted sites to benefit your website ranking, they must be related to your website theme.

If you suspect that loss of Google trust has caused Supplemental Results on your website, then re-assess your SEO strategy away from reciprocal linking and concentrate on building quality content to attract more one way links. Also consider removing reciprocal links to non related sites, particularly if you have a 'reciprocal link directory' on your site. Remember that reciprocal linking should not be done to excess - so consider more worthwhile methods of website promotion, such as article writing and submission to decent article sites like Ezine Articles.


* Low Page Rank -
One of the most common causes of Supplemental Result problems is not enough homepage Google Page Rank (PR) to ensure that all internal pages of a website achieve full indexing. This is made worse where websites have lots of pages resulting in PageRank being spread too thin. Since Page Rank is passed between pages via both internal and external links the importance of having quality links to your site and decent internal navigation are paramount to get out of Supplemental Results. Matt Cutts SEO Blog singles out low Page Rank as the most common cause of Supplemental Result pages, in his May 2007 article Google Hell. Low Page Rank in itself is frequently caused by a lack of inbound links from other websites (hence it's a common problem on a new website). Bear in mind too that Page Rank reductions have also occurred on many sites due to Google's devaluation of links from low quality sources such as link exchange directories. Reduced homepage Page Rank caused by link devaluation can then directly cause Supplemental Results to show on previously fully indexed content.

It's worth checking the number of "in-links" to your site with Yahoo Site ExplorerIf few in-links are shown, then this could well be the cause of any supplemental pages. After the Google Big Daddy update, Google became more reluctant to fully index websites with few inbound links (also referred to as in-links or backlinks) as rightly or wrongly they weren't deemed important enough. Where a homepage has Page Rank 1 or 2 sometimes only the homepage of a domain may be fully indexed with all other internal pages showing as Supplemental Results or not indexed at all (depending on internal navigation structure of the site). In extreme cases, where a website has few inbound links it may not even be listed in Google, even if is submitted for inclusion by the webmaster as Google generally only indexes sites by following hyperlinks from other Worldwide Web sites.

* Duplicate Content -
Supplemental Result pages can be the result of duplicate content or content which is too similar to pages which can be found elsewhere on the World Wide Web. Even web pages on the same website domain which are very similar to each other cause problems. Hence, getting out of Google Supplemental Results can require some content re-writing in some cases. Start by checking for duplicate content by using Copyscape. This free service can help find plagiarised or duplicate content on the web. Enter the URLs of your Supplemental Result pages into a Copyscape search window and check for plagiarised content on other web domains. If similar content is found, you'll need to correct the problem - either by contacting the webmaster of the site who has plagiarised your content or by re-writing your page/s to eliminate duplicate content. Google has got tougher on duplicate content and pages which have similar structure and content will often now be listed as Google Supplemental Results.

* Too Much Content Similarity -
Google Supplemental Results can also be caused by having the same HTML title and a similar META description on each web page, especially where there is a significant amount of duplicate content between pages, such as on an E-commerce site. This problem can often be made worse by excessively large website navigation systems duplicated on all web pages.

One Supplemental Result example we saw used a pull-down form based navigation system which had hundreds of links to other web pages all individually listed. Each webpage was 125KB big, mostly made up from the identical website navigation code. This kind of website navigation system can "bury" the unique content of each page increasing similarity between web pages and making the problem of Supplemental Results much more likely. To get out of Supplemental Results, try to reduce duplicate content or too much similarity between pages.

* Poor Website Navigation -
Where most web pages on a particular domain show as Google Supplemental Results and they have unique content, check the Page Rank (PR) of the homepage. If the Google PR is less 3, then Google may only fully index the most prominent pages in the domain which are one click away from the homepage in the website navigation system.

Often, the web pages which escape becoming supplemental results are those which are directly linked to from the homepage by means of a static hyperlink. Links from other fully indexed pages of your site to the supplemental pages will also help to get out of the Google Supplemental index.

* Mod Rewrite Website Content -
Care should be taken when doing a website mod rewrite to avoid getting into the Google Supplemental Results for the re-written pages. Mod rewrite encompasses changing website URL's and/or moving website o webpage content. A full definition of mod rewrite can be found at Wikipedia. Changing the URL's of existing, established website pages can cause search engine indexing problems if done improperly. Often search engines will see the new page URL's as duplicates of pages they already have in cache, leading to Supplemental Result issues on the modified or re-written pages. To avoid this, redirect the old web pages to their individual new URL's using a search engine friendly 301 re-direct. This can be set up in the form of a simple .HTACCESS file and works well on all but Microsoft hosted web servers.

* Supplemental Results Google Video -
Watch the Matt Cutts Supplemental Results Help Video (he's a Google engineer) for more helpful advice and tips on getting out of Supplemental Results.

Check out for Getting out of Supplemental Results