THE ROBOTS.TXT FILE
You know that search engines have been created to help people find information quickly on the Internet,
and the search engines acquire much of their information through robots
(also known as spiders or crawlers), that look for web pages for them.
The spiders or crawlers robots explore the web looking for and recording all kinds of information.
They usually start with URL submitted by users, or from links they find on the web sites, the sitemap
files or the top level of a site.
Once the robot accesses the home page then recursively accesses all pages linked from that page.
But the robot can also check out all the pages that can find on a particular server.
After the robot finds a web page it works indexing the title, the keywords, the text, etc.
But sometimes you might want to prevent search engines from indexing some of your web pages like news
postings, and specially marked web pages (in example: affiliate´s pages), but whether individual robots
comply to these conventions is pure voluntary.
ROBOTS EXCLUSION PROTOCOL
So if you want robots to keep out from some of your web pages, you can ask robots to ignore
the web pages that you don´t want indexed, and to do that you can place a robots.txt file on the local
root server of your web site.
In example if you have a directory called e-books and you want to ask robots to keep out of it, your
robots.txt file should read:
User-agent: * Disallow: e-books/
When you don´t have enough control over your server to set up a robots.txt file,
you can try adding a META tag to the head section of any HTML document.
In example, a tag like the following tells robots not to index and not to follow links on a
meta name=”ROBOTS” content=”NOINDEX, NOFOLLOW”
Support for the META tag among robots is not so frequent as the Robots Exclusion Protocol,
but most of major web indexes currently support it.
If you want to keep the search engines out of your news postings, you can create an an
“X-no-archive” line in of your postings’ headers:
But although common news clients, allow you to add an X-no-archive line to the headers of your news
postings, some of them don´t permit you to do so.
The problem is that most search engines assume that all information they find is public unless
So be careful because though the robot and archive exclusion standards may help keep your material
out of major search engines there are some others that respect no such rules.
If you’re highly concerned about the privacy of your e-mail and Usenet postings, you must use
some anonymous remailers and PGP. You can read about it here:
Even if you are not particularly concerned about privacy, remember that anything you write
will be indexed and archived somewhere for eternity, so use the robots.txt file as much
as you need it.
Written by Dr. Roberto A. Bonomi