THE ROBOTS.TXT FILE
KEEP ROBOTS OUT OF YOUR WEB SITE
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 particular page:
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.
USENET NEWS POSTINGS
If you want to keep the search engines out of your usenet news postings,
you can create an an "X-no-archive" line in of your postings' headers:
X-no-archive: yes
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 marked otherwise.
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:
http://www.well.com/user/abacard/remail.html http://www.io.com/~combs/htmls/crypto.html
http://world.std.com/~franl/pgp/
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
