What's benefits of sitemaps?

I think it make my site to index decreasing.

 

I doubt it. If you now have fewer pages index ask your self if it would be possible that you got some kind of penalty for black hat practices, over optimization...

 

sitemap is a file which is crawled by search engine and it will get information about your website from the URL's which you have in your sitemap.

 

Won't be because of your sitemap if your index status is decreasing.

 

Sitemap is built to submit all urls of your site to google and yahoo, but it still up to the search engines to pick up which urls to be included into their database.

 

Sitemap help you to index your web pages in google indexing or other search engine indexing. its a list of pages on your site

 

Sitemap is very useful to site.

 

Sitemap helps your inner pages be indexed faster. Make it sure that it has no broken links.

 

sitemap helps you give more hits from google or other search engine motors.

 

A sitemap is very important if you plan to conduct a good seo campaign.

 

A sitemap helps as far as getting indexed faster by google.A sitemap is very important for SEO Purpose.!!!!!!!!!!!!!!!

 

Sitemap is really important for your site if you maintain the links properly, without any broken links and spam links.

So be aware of broken and spam links in your site and remove it as early as possible from site.

If google or any other search engines index those urls your site will be penalized.