The Robots.txt file is a simple text file placed on your web server which tells web crawlers like Googlebot if they should access a file or not. The Robots Exclusion Protocol (REP) is a group of web standards that regulate web robot behavior and search engine indexing. The REP consists of extensions, tags, and other elements.
The Robot.txt file is a fundamental part of the search engine, as the bots interact with it. Improper usage of the file can hurt your ranking since Robot.txt controls the way search engine spider see and interact with your web pages.
There are three important things that any webmaster should do when it comes to the robots.txt file:
• Determine if you have a robots.txt file
• If you have one, make sure it is not harming your ranking or blocking content you don’t want to be blocked
• Determine if you need a robots.txt file
You may not even need to have a robots.txt file on your site. In fact, it is often the case you do not need one. When you do not have a robots.txt file the search engine robots like Googlebot will have full access to your site. This is a normal and simple method that is very common.
Reasons you may want to have a robots.txt file:
• You have content you want to be blocked from search engines
• You are using paid links or advertisements that need special instructions for robots
• You want to fine tune access to your site from reputable robots
• You are developing a site that is live, but you do not want search engines to index it yet
• They help you follow some Google guidelines in some certain situations
• You need some or all of the above, but do not have full access to your server and how it is configured
Each of the above situations can be controlled by other methods, however, the Robots.txt file is a good central place to take care of them and most webmasters have the ability and access required to create and use a Robots.txt file.
Reasons you may NOT want to have a robots.txt file:
• It is simple and error-free
• You do not have any files you want or need to be blocked from search engines
• You do not find yourself in any of the situations listed in the above reasons to have a robots.txt file
Be aware that a Robots.txt file is a publicly available file. Anyone can see what sections of a server the webmaster has blocked the engines from. This means that if an SEO has private user information that they don’t want publicly searchable, they should use a more secure approach—such as password protection—to keep visitors from viewing any confidential pages they don’t want to be indexed.
If you decide that you need a Robot.txt file, you can create one by yourself. Before doing so, it is important to know that malicious crawlers are likely to completely ignore robots.txt and as such, this protocol does not make a good security mechanism, so you will have to think of additional ways to protect your website.
Here you can find detailed instructions on how to create a Robot.txt file.