Duplicate Content

[brancook]

I used a tool to measure the percentage of duplicate content between two pages on my website. The tool told me that the 2 pages had about 40% duplicate content. Is that enough to get one of my pages put into the supplemental index. Because as of right now one of the pages is in the supplemental index.

[new_seo]

I don't think 40% duplicate content can be a serious issue for supplemental index. There are lots and lots of other factors for which a page can go to supplemental index, except duplicate content.

1. Orphaned pages.
2. Same Title and Heading tags in different pages.
3. Canonical issue (Like www.example.com, example.com/, www.example.com/index.html, example.com/home.asp)
4. Lack of content
5. Lack of back Link Power etc.

Figure out the actual problem of your page and try to over come that.

[brancook]

I'm not sure if I understand what you mean by example number 3.

[new_seo]

You will find some great info over here.
[mattcutts.com...]