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 Author
Article by Sumantra Roy.
Sumantra is one of the most respected and recognized search
engine positioning specialists on the Internet. For more
articles on search engine placement, subscribe to his 1st
Search Ranking Newsletter by going to:
http://www.the-easy-way.com/newsletter.html
0 comments:
Post a Comment