I dont know about this thing and now i want to know. Please tell me abt robot.txt what is it and how it works
it is a special file that tells search engines what they can and can't index and include in search results. It is basically a file that holds instructions for search engine spiders.
You only need a robots.txt file if you have pages that you wouldn't like search engines to index. The lack of a robots.txt file doesn't affect your SERPS and search engines will index your website normally.
You can now place a reference to your sitemap in a robots.txt and more and more of the bots are starting to recognize this.