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Like most e-mail users, you probably get a
ton of unsolicited messages, and you may be
getting more and more every month. Filtering
software can help you sort out obvious spam,
but it still takes time to examine all the
e-mails a spam filter puts into the
in-between category of "it may be spam, it
may not be." This is spam that could
contain a virus, be a phishing attempt or it
could merely be offering pharmaceuticals or
investment opportunities. Wouldn't you
rather avoid some of that spam in the first
place?
In a series of experiments, the center for
democracy and technology, a nonprofit group
based in Washington DC, created dozens of
new e-mail addresses and then used them in
various ways to see which addresses would
receive the most spam.
After months of public exposure, the e-mail
addresses that received almost all -- -- a
whopping 97% -- -- of the thousands of
pieces of spam that came in were those
posted on web pages. Addresses that had been
used only to register at e-commerce sites,
for example, received little or no spam.
Professional spammers, constantly scan the
Web using high-speed programs known as
harvesters to capture visible e-mail
addresses. Harvesting addresses with a robot
spider in this way is illegal in the US
under the CAN-SPAM Act, but that hasn't stopped the
practice.
Using a spider, a high speed connection and
a reasonably powerful computer, over ten
thousand email addresses can be harvested in
a single hour.
To understand how fast an email address
database can be built, consider the
following numbers that are typical of spider
speeds:
64 websites can be visited at the same time
time.
It takes an average of 20 seconds to spider
a website.
Based on those numbers, if they only get one
email address from each website visited, you
would be looking at a spammer adding 11,520
email addresses to their list per hour.
Let the spider run for a day and we are
talking about more than 275,000 email
addresses.
This is one reason why everyone in a company
will frequently get the same piece of spam
at the same time -- a spammer has crawled
your company website and gotten the
addresses of everyone that is listed on the
site.
Does this mean you can never put your e-mail
address on a web page? Not at all. If you
use the right methods, you can let people
know how to get in touch with you -- -- and
still keep spammers from harvesting your
address.
One of the easiest ways is to spell out the
"@" sign and the period, like this:
support at eightdollarwebhosting dot com.
In the center's study, addresses that had
been obscured in this simple way on web
pages did not receive a single piece of spam!
Unfortunately, though the spammers' current
harvesting software isn't smart enough to
replace the spelled-out symbols, this won't
be true for long, as the programs are
continually improving. To insure that
harvesters can't read your address now or in
the future, stronger steps are needed.
To make your address truly invisible to
harvesters, but visible to human visitors,
display it only as a graphic. Open
Microsoft's Paint, Paint Shop Pro, Photoshop
or a similar graphics application and select
text mode. Type your address, switch to the
select tool, and select the area where your
address appears, saving it as a GIF file.
Post the graphic on your web page, and
you're done.
Although optical character recognition (OCR)
programs can read letters and numbers in
image files, it's unlikely that a harvesting
program will ever use OCR. Setting
harvesting programs to scan every single image on
the World Wide Web would severely slow them down and,
in the end, wouldn't be cost-effective.
If you have an e-mail link on your site,
it's very important that the HTML code
behind it doesn't contain your e-mail
address in plain text. Harvesting programs
actually read code, not the characters
visible in a browser.
To protect your clickable links from being
harvested, you should encrypt the portion of
your code that includes your e-mail address
using JavaScript.
Using JavaScript encryption on the
e-mail address on your webpage,
 becomes
%61%61%75%64%65%74%74%65%40%61%75%64%65%74%74%65%69%6E%74%65%72%6E%65%74%2E%63%6F%6D.
This will make your e-mail address, not only
unreadable to the human eye, but also
unreadable to harvesting programs, which
can't take the time to decode all of the
JavaScript on web pages. Web browsers, however,
have no trouble when it comes to
interpreting the code and will show the
encrypted code as
.
A website that will instantly encrypt your email
address (or any HTML code) for free is:
http://webdeveloper.earthweb.com/repository/javascripts/2004/03/398171/index.html
Keep in mind, however, that some 10% of web
users usually have disabled JavaScript in
their browsers, and, therefore will not be
able to see your link, so it is important to
display your address both as a graphic and
as a clickable JavaScript link.
Using these techniques the
spamming harvesters will visit your website
and move on when they can't see any usable
email addresses. So to your
insure your computer's health....use stealth. |
