What is robots.txt file?

Working with robots.txt file

Advantages of robots.txt

Disadvantages of robots.txt file

Optimization of robots.txt file

Using robots.txt file

What is robots.txt file?

The robots.txt file is an ASCII text file that has specific instructions for search engine robots about specific content that they are not allowed to index. These instructions are deciding factor of how a search engine indexes your website's pages. The universal address of robots.txt file is: www.domain.com/robots.txt . This is first file that a robot visits. It picks up instructions for indexing site content and follows them. This file contains two text fields. Lets study this robots.txt example :

User-agent: * Disallow:

The User-agent field is for specifying robot name for which access policy follows in Disallow field. Disallow field specifies URLs which specified robots have no access to. A robots.txt example :

User-agent: * Disallow: /

Here "*" means all robots and "/ " means all URLs. This is read as, " No access for any search engine to any URL" Since all URLs are preceded by "/ " so it bans access to all URLs when nothing follows after "/ ". If partial access has to be given, only banned URL is specified in Disallow field. Lets consider this robots.txt example :

# Research access for Googlebot. User-agent: Googlebot Disallow:

User-agent: * Disallow: /concepts/new/

Here we see that both fields have been repeated. Multiple commands can be given for different user agents in different lines. The above commands mean that all user agents are banned access to /concepts/new/ except Googlebot which has full access. Characters following # are ignored up to line termination as they are considered to be comments.

Working with robots.txt file : -

The robots.txt file is always named in all lowercase (e.g. Robots.txt or robots.Txt is incorrect)

Wildcards are not supported in both fields. Only * can be used in User-agent fields' command syntax because it is a special character denoting "all". Googlebot is only robot that now supports some wildcard file extensions. Ref: http://www.google.com/webmasters/faq.html#12

The robots.txt file is an exclusion file meant for search engine robot reference and not obligatory for a website to function. An empty or absent file simply means that all robots are welcome to index any part of website.

Only one robots.txt file can be maintained per domain.

Website owners who do not have administrative rights cannot sometimes make a robots.txt file. In such situations, Robots Meta Tag can be configured which will solve same purpose. Here we must keep in mind that lately, questions have been raised about robot behavior regarding Robot Meta Tag. Some robots might skip it altogether. Protocol makes it obligatory for all robots to start with robots.txt thereby making it default starting point for all robots.

Separate lines are required for specifying access to different user agents and Disallow field should not carry more than one command in a line in robots.txt file. There is no limit to number of lines though i.e. both User-agent and Disallow fields can be repeated with different commands any number of times. Blank lines will also not work within a single record set of both commands.

Use lower-case for all robots.txt file content. Please also note that filenames on Unix systems are case sensitive. Be careful about case sensitivity when defining directory or files for Unix hosted domains. You can use this great tool to check your robots.txt from www.searchengineworld.com:

The robots.txt Validator

Please note that full path to robots.txt file must be entered in field.

Advantages of robots.txt file : -

Protocol demands that all search engine robots start with robots.txt file. This is default entry point for robots if file is present. Specific instructions can be placed on this file to help index your site on web. Major search engines will never violate Standard for Robots Exclusion.

The robots.txt file can be used to keep out unwanted robots like email retrievers, image strippers etc. The robots.txt file can be used to specify directories on your server that you don't want robots to access and/or index e.g. temporary, cgi, and private/back-end directories. An absent robots.txt file could generate a 404 error and redirect robot to your default 404 error page. Here it was noticed after careful research that sites that do not have a robots.txt file present and had a customized 404-error page, would serve same to robots. The robot is bound to treat it as robots.txt file, which can confuse it's indexing. The robots.txt file is used to direct select robots to relevant pages to be indexed. This specially comes in handy where site has multilingual content or where robot is searching for only specific content. The need for robots.txt file was also felt to stop robots from deluging servers with rapid-fire requests or re-indexing same files repeatedly. If you have duplicate content on your site for any reason, same can be controlled from getting indexed. This will help you avoid any duplicate content penalties.

Disadvantages of robots.txt file : -

Careless handling of directory and filenames can lead hackers to snoop around your site by studying robots.txt file, as you sometimes may also list filenames and directories that have classified content. This is not a serious issue as deploying some effective security checks to content in question can take care of it. For example if you have your traffic log on your site on a URL such as www.domain.com/stats/index.htm which you do not want robots to index, then you would have to add a command to your robots.txt file. As an example:

User-agent: * Disallow: /stats/

How Search Engines Work

Before delving into specific elements, it’s necessary to understand how search engines work. True search engines (as opposed to directories like Yahoo!) use a program called a “robot” or “spider” to “crawl” web while gathering and indexing information they find. A searcher receives results of these crawls when s/he conducts a search. Sounds simple, right? Unfortunately, every search engine (and literally thousands of engines exist) has its own criteria for indexing sites, and further criteria for determining ranking of sites. It’s easy to see why S.E.O. consultants can make a handsome living – it’s virtually impossible for a single webmaster to know all of various rules that will optimize his/her site for every engine.

Feeling Overwhelmed Yet?

While a search engine optimization consultant can provide a greater amount of detailed knowledge for an individual web master, experts tend to agree that there are a few rules that almost anyone can apply to optimize his/her site.

First, while thousands of search engines exist, most surfers do their searching on a handful of sites. Yahoo! generally accounts for half of all web searches. While they charge a fee for simply considering a business listing in their directory (currently $299), many business people may find that a reasonable investment, considering popularity of this portal. Among true search engines, most popular by far are Google and Overture. It’s important to know that many search engines actually get there results from these giants, so applying rules that work for these two can help get your site listed in many engines.

Optimizing You Site

In order to make sure your site is listed in searches that directly apply to your type of business, it’s essential to use best keywords and phrases. Keywords are words that searchers use to find web sites that will give them information they want. In order to take advantage of power of keywords, you must find out what keywords and key phrases are most popular among searchers you want to attract to your site, so you may want to consider using a service like Wordtracker (http://www.wordtracker.com) to find out words and phrases that searchers are using. Once you’ve determined this, you want to place those words and phrases at points in your page most likely to be noticed by search engines. Experts tend to agree that best places to use keywords are in your page title, your page’s copy, and in site’s meta tags.