Spam: Poison Pill
A common way for spammers to create their vast lists of email
addresses is to cull web pages for "mailto:" tags. There are
many different programs, available for small to huge costs,
which will do this automatically, easily and efficiently.
I monitor my web site log files on a regular basis, and I'm
always amazed at the vast numbers of spam harvesting programs
that regularly scan my pages. Not only do these obnoxious things
steal email addresses, they use bandwidth which I pay for
without any kind of compensation. I put up my web pages for
people to read not for some scumbag spammer to scan them.
There are many ways to combat the spammer. None of these methods
are perfect. As in any war, both sides are continually
developing new weapons to use against the other. New methods
work for a short time until the enemy comes up with
countermeasures and overcomes the weapon.
One of the more effective ways to confuse the spammer (not hard
because they don't tend to be very bright) is the "poison pill"
defense. This consists of handing the spam harvesting robots
some pages which appear juicy, full of yummy email addresses
ripe for the picking.
The email address on these pages are fake. They have nothing to
do with reality and exist only to choke the spam robots, causing
them to overflow and possibly even crash.
Here's how a typical poison pill works. A script is created
which performs all of these tasks. It is important that the
scripting be done on the server, so CGI, ASP, PHP or a similar
scripting language must be used. Server side scripting must be
used because many spam robots are not smart enough to understand
client-side scripting languages such as JavaScript.
The script creates a page which appears in all ways to be a
normal document in a web site. The page may include some text
informing human visitors of the intention (this is important so
any people who see the page are not confused).
It also needs to include a meta tag informing all robots not to
index the page. This is critical, as you do not want robots such
as googlebot or scooter (the spiders for Google and Altavista,
respectively) seeing this stuff. Don't worry, spam harvesters
ignore these meta tags.
The script gives the page a name, usually randomly picked from a
database or made up somehow, and fills it with a few dozen (at
the most) email addresses. These email addresses are cleverly
created to appear perfectly valid but actually are useless -
they are just made up.
Links to other fake pages are created for the spam harvester to
follow. Any robot (or human being, for that matter) that follow
these links will find similar pages, full of desirable email
addresses.
Depending upon the robot, it's possible the spammer could gather
tens of thousands of totally fake, unusable email addresses
before his robot blows itself out of the water. It's even better
if the robot survives, as the spammer now wastes his time
sending messages to nonexistent email addresses.
In the meantime, the harvester has been lured away from valid
pages which may or may not contain email addresses.
My site, Internet Tips and Secrets, uses one of these poison
pills. It is called wpoison and it really works well. If you
want to see it, look at this page.
http://www.internet-tips.net/cgi-bin/guestlist.pl
If you want to get a copy for yourself, check out the wpoison
page.
http://www.monkeys.com/wpoison/
This is just another weapon in the war against spam.
Is it effective?
I know from personal experience that it does trap spam robots,
and it does seem to lure them away from real, useful email
addresses.
Is it ethical?
I believe so, as long as you are careful to include the meta
tags to inform "good" robots to leave the pages alone as well as
some text to let your visitors know what's going on.
It's not as satisfying as spamcop.net, and there is no where
near that pleasant glow of success upon learning that some scum
spammer has had his ISP cancel his account, but the poison pill
is useful nonetheless. My advice is to include it in your
arsenal along with the other weapons and tools at your disposal.
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