what is importance of robot.txt in seo?

Hello Guys,
Please tell me what is importance of robot.txt in seo? i am new in seo field i want to know more about it, so please share your reviews about its and how can be make robot.txt useful for seo.
Thanks.

Robots.txt file is in the root directory of a website which has been created to direct the activity of search engine crawlers or spiders.

Robots text file are those which forced to search engine how to crawl and index your site or web pages.
It is great when search engines frequently visit your site and index your content but often there are cases when indexing parts of your online content is not what you want.

It helps in directing search engine spiders to follow and index contents found on your site.

Robot.txt is the notepad file you have a crawl you page which one that mostly not use so you add that one page in robot.txt so that page is online so client see very well but Google is not crawl that one page....

Robot.txt is a file which contains the instruction for the crawler or bots of search engines. It instruct the search engine crawler about the web pages which should they crawl and which do not.

You can set your robot.txt in your webmaster tools, it usually largely use by webmaster to set that which URL to follow and index and which URL not to follow and index to maintain their site quality .

Robot.txt is a file which prevents files, folders from being cached in search engine. You can specify files and folders that are not to be crawled in search engine for security purpose you must do it.

It provide the search engine crawlers permission to follow or index particular page or content or image or link of your web page.

Robot.txt file give instruction to google crawler or robot which file not to index or crawl. Basically robot.txt file restrict google crawler to crawl written page in file.

Hello Friends,

Robot.txt files tell your instructions to a search engine robot. It depends on what you what it to do. If you don't have the robot.txt file then when a robot visits your site and if it doesnt find the file, it will start to visit all the pages and contents of your site. These files are like walls which helps in preventing some files like java scripts, some images or any other files from indexing. It is also important to make a note that it is not a method that prevents search engines from crawling your site. So it is important to create a robot.txt file

Thanks and Regards
seoworldclass.com

There are many search engine are available on the web. When a search engine crawler comes to the site, it will look for a special file on your site. That file is called robots.txt and it tells the search engine spider, which Web pages of your site should be indexed and which Web pages should be ignored.

It is important to clarify that robots.txt is not a way from preventing search engines from crawling your site (i.e. it is not a firewall, or a kind of password protection) and the fact that you put a robots.txt file is something like putting a note “Please, do not enter” on an unlocked door – e.g. you cannot prevent thieves from coming in but the good guys will not open to door and enter. That is why we say that if you have really sensitive data, it is too naive to rely on robots.txt to protect it from being indexed and displayed in search results.

As per my info; Robot.txt is extremely helpful to stop the google crawlers where you do not need them to cache your WebPages or admin pages.

robot.txt is basically a file which use to stop Google's crawler to visit any particular pages which site administrator not want to read by Crawler.