Page
Cloaking - To Cloak or Not to Cloak
Teacher:
Sumantra Roy
Page 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.
About the teacher:
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/
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
http://www.1stSearchRanking.com/newsletter.htm |
