Copyright 2005 Sumantra RoyPage cloaking can broadly be defined as a technique used to
deliver different web pages under different circumstances.
There are two primary reasons that people use page cloaking:
i) It allows them to create a separate optimized page for
each search engine and another page which is aesthetically
pleasing and designed for their human visitors. When a
search engine spider visits a site, the page which has been
optimized for that search engine is delivered to it. When a
human visits a site, the page which was designed for the
human visitors is shown. The primary benefit of doing this
is that the human visitors don't need to be shown the pages
which have been optimized for the search engines, because
the pages which are meant for the search engines may not be
aesthetically pleasing, and may contain an over-repetition
of keywords.
ii) It allows them to hide the source code of the optimized
pages that they have created, and hence prevents their
competitors from being able to copy the source code.
Page cloaking is implemented by using some specialized
cloaking scripts. A cloaking script is installed on the
server, which detects whether it is a search engine or a
human being that is requesting a page. If a search engine
is requesting a page, the cloaking script delivers the page
which has been optimized for that search engine. If a human
being is requesting the page, the cloaking script delivers
the page which has been designed for humans.
There are two primary ways by which the cloaking script can
detect whether a search engine or a human being is visiting
a site:
i) The first and simplest way is by checking the User-Agent
variable. Each time anyone (be it a search engine spider or
a browser being operated by a human) requests a page from a
site, it reports an User-Agent name to the site. Generally,
if a search engine spider requests a page, the User-Agent
variable contains the name of the search engine. Hence, if
the cloaking script detects that the User-Agent variable
contains a name of a search engine, it delivers the page
which has been optimized for that search engine. If the
cloaking script does not detect the name of a search engine
in the User-Agent variable, it assumes that the request has
been made by a human being and delivers the page which was
designed for human beings.
However, while this is the simplest way to implement a
cloaking script, it is also the least safe. It is pretty
easy to fake the User-Agent variable, and hence, someone
who wants to see the optimized pages that are being
delivered to different search engines can easily do so.
ii) The second and more complicated way is to use I.P.
(Internet Protocol) based cloaking. This involves the use
of an I.P. database which contains a list of the I.P.
addresses of all known search engine spiders. When a
visitor (a search engine or a human) requests a page, the
cloaking script checks the I.P. address of the visitor. If
the I.P. address is present in the I.P. database, the
cloaking script knows that the visitor is a search engine
and delivers the page optimized for that search engine. If
the I.P. address is not present in the I.P. database, the
cloaking script assumes that a human has requested the
page, and delivers the page which is meant for human
visitors.
Although more complicated than User-Agent based cloaking,
I.P. based cloaking is more reliable and safe because it is
very difficult to fake I.P. addresses.
Now that you have an idea of what cloaking is all about and
how it is implemented, the question arises as to whether
you should use page cloaking. The one word answer is "NO".
The reason is simple: the search engines don't like it, and
will probably ban your site from their index if they find
out that your site uses cloaking. The reason that the
search engines don't like page cloaking is that it prevents
them from being able to spider the same page that their
visitors are going to see. And if the search engines are
prevented from doing so, they cannot be confident of
delivering relevant results to their users. In the past,
many people have created optimized pages for some highly
popular keywords and then used page cloaking to take people
to their real sites which had nothing to do with those
keywords. If the search engines allowed this to happen,
they would suffer because their users would abandon them
and go to another search engine which produced more
relevant results.
Of course, a question arises as to how a search engine can
detect whether or not a site uses page cloaking. There are
three ways by which it can do so:
i) If the site uses User-Agent cloaking, the search engines
can simply send a spider to a site which does not report
the name of the search engine in the User-Agent variable.
If the search engine sees that the page delivered to this
spider is different from the page which is delivered to a
spider which reports the name of the search engine in the
User-Agent variable, it knows that the site has used page
cloaking.
ii) If the site uses I.P. based cloaking, the search
engines can send a spider from a different I.P. address
than any I.P. address which it has used previously. Since
this is a new I.P. address, the I.P. database that is used
for cloaking will not contain this address. If the search
engine detects that the page delivered to the spider with
the new I.P. address is different from the page that is
delivered to a spider with a known I.P. address, it knows
that the site has used page cloaking.
iii) A human representative from a search engine may visit
a site to see whether it uses cloaking. If she sees that
the page which is delivered to her is different from the
one being delivered to the search engine spider, she knows
that the site uses cloaking.
Hence, when it comes to page cloaking, my advice is simple:
don't even think about using it.
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Article by Sumantra Roy. Sumantra is one of the most
respected search engine positioning specialists on the
Internet. To have Sumantra's company place your site at the
top of the search engines, go to
http://www.1stSearchRanking.com/t.cgi?3455_h For more
advice on how you can take your web site to the top of the
search engines, subscribe to his FREE newsletter by going
to
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