While working with India Debt Recovery website, I have seen that Google caching index.jsp page individually considering that page as another page. Google indexed that page because the Web-developer has put a link index.jsp on “Home” anchor text, in place of full url of the site.
I am so amazed to see that, when I have already changed the index page, but still Google not understanding that page is one same page. And even he is not releasing his boats to re-cache that page. I explain how, there is a url laddiweb.blogspot.com this is a page for Google and laddiweb.blogspot.com/index.html this is another page for Google not same. While both returns the same results.
Another big problem is that Google can consider a site spam, when two different urls returns the same content. He must compare two page’s content and will remark as Duplicate content.
This is very important point to remember that, do never put a link in your site that return same page but different url, The best way is to use full url of the webpage inside the whole website.
Therefore, this is a big issue for search engines like Google that do never put a link index.html or something but use full url for best Optimization.