This article will guide you through the main reasons for the pages to get listed in this index, and most importantly, the way out. If you have an existing site, there is a high chance that you can have extra pages in the index, so use this as a reference, and be sure to follow the steps outlined here.

First, for those who are new to this subject.
What is the supplemental index? Here's the short answer ... Google actually has two indexes, called the "Main Index" and another known side as "complementary." One way to verify that you are looking for an additional result is that you can see "Supplemental Result" in green on the bottom line of any list due to Google.

Why go to the home pages of supplement?
There are many obvious and some not so obvious reasons for this, but not duplicate content are the two main current. A "dynamic", url, ie with many variables, or a page that is deep in the structure of the site also realizes this. A tip on linking: If you are making excessive reciprocal links, link buying / selling or linking to spam neighborhoods ... Stop! Google has algorithms very low confidence in the incoming and outgoing links from those sites.

Solutions to exit the supplemental index.
Now that you know what this is and what index your pages do the same, I'll go over ways that you can leave and return to it belong, the main index. I groups of twos, as they are co-related to:
1. Duplicate content and quality of content. All meta tags should be unique. All pages have common elements such as navigation, footer, etc. Make sure your page has enough unique content to compensate for these elements and that is providing quality as well.
2. Dynamic URL and site structure. Keep all URLs as "static" as possible. Why go 3-4 variables if there is an easier way? And each page should be 2-3 clicks from the homepage, in terms of site structure. Please refer to Google, the best SEO Practices - Part 4.
3. Your internal links and profile. His map, which is a very important component of its internal links, include links to all pages of your site, and must be linked (usually in the footer) of each page. And the profile of your site overall link directly affects the level of confidence it gives Google, which affects the PageTrust, less trust often results in more additional pages.

Again, as I said before, make it easy for Google, and make it easier on you