What is the need of schema.org? Where I can get best & free schema creator tools?

Schema.org markup allows search engines to understand the information on web pages in short hand and provide richer search results in order to make it easier for users to find relevant information on the web.

There are so many online schema tools are available-

http://getschema.org/index.php/Main_Page

http://schema-creator.org/

http://www.microdatagenerator.com/get-started/

http://clixlogix.com/schema-creator/

http://blog.raventools.com/free-schema-creator/