Filters: What you need to know!
By Dori Friend
an active email marketer, correctly directing your email
campaigns has never been more critical. As you are well
aware, actively managing your bounces or avoiding spam
filters completely is ideal. You want to ensure that the
greatest number of intended recipients actually get reached
with the message that they asked for!
Recently, it has been reported that Yahoo! blocks as much
as 22% of email, AT&T blocks 12% and AOL, with some
30 million subscribers, blocks 18%. Marketers themselves
estimate that as much as 15% of their legitimate e-mail
communication (emails for which recipients have opted-in)
is getting labeled as spam.
Think about it if you sent 100,000 pieces of direct
mail through the post office and 15,000 of them got thrown
away by the mail carriers would you be happy? Consumers,
on the other hand report that roughly one-third of desired
email is not getting through to them, because it is being
blocked by spam filters.
To be sure, the filters themselves are not perfect and
often times they err on being "over protective."
A good number of them have even become quite aggressive
as of late, and the number of spam filtering options is
growing as well. As many as 150 companies now offer spam
The spam filter technology is getting "smarter"
too. For example, some servers (known as challenge systems)
send e-mail back to the original sender and require a
reply before they forward the email onto the account holder.
The idea here is that a machine cannot reply to a request
for specific information, so if the email is genuine it
will be answered and then forwarded. America Online recently
announced a new spam filter that can actually "learn"
the preferences of each of their subscribers. This will
be an interesting technology to watch.
The filtering itself can be broken down into three groups:
Content based filtering, Volume based filtering and Blacklist
Content-based filters block email messages that appear
to be spam because they contain words, symbols and other
indicators that identify the email as potential spam.
These are where "triggers" come into play.
Volume-based filters are used to counter the high-volume
demand from large junk mailers.
For instance, if email messages exceed a certain pre-determined
limit, like messages sent per second , the email messages
may be blocked or redirected to a junk mail folder.
Blacklists are lists of IP addresses that are associated
with known and alleged spammers. Reportedly, there are
close to 300 spam blacklists in use today by ISPs and
system administrators (ouch)!
The Internet spam filters work by reviewing incoming email
and "checking" the file for certain factors.
Depending on what these filters find or dont find,
points are added to or taken away from a scoring system.
These filters (you may be familiar with such names as
SpamAssassin, Bogofilter, and SpamProbe) look for certain
patterns in your email, and assigns "spam points"
depending on certain words, phrases, or even colors!
If your score is 5.0 or higher, your email subject line
may be edited and "* SPAM*" appears at the start
of your email, or your email is redirected to a "bulk"
type of mailbox (how RUDE)! The key point to remember
about the numbers is this: the lesser the score the better
(kind of like golf)!
If we were to categorize the two primary areas where spam
filters err, they would be in the areas of "false
negatives" and "false positives." A false
negative is when an email that is indeed spam gets through
the filter, and a false positive is when a legitimate
email gets caught in the filtering system.
what can you, as a legitimate e-mail marketer do to ensure
that your messages reach the intended recipients?
marketers are doing a combination of things to combat
this aggressive filtering. One way is to "tailor"
their messages so as to stay away from filter "triggers".
can also go it alone, and try to avoid the spam filters,
but beware, trying to outsmart the email filters is a
daunting challenge There do exist some words that are
generally believed to be "triggers".
like LIVE, PICS, PROTECT, NEWS, CREDIT, SOLUTION, FREE,
MORTGAGE, WORK and INTERNET.
The best thing is to do with regard to staying away from
triggers is to frame your messages so that they have the
best chance of getting through these filters. Make sure
that your clients confirm the fact that they have "opted-in".
Send them a confirmation e-mail to the address they specified
and ask them to reply that they indeed want to receive
mail from you. Once this is done, be sure to ask them
to add your e-mail to their address book.
I bet that the recent "DO NOT CALL" list could
easily be morphed into a "DO NOT EMAIL" nationwide
list. If it does, you already have your proof with your
confirmed list that your clients want to hear from you!
Another good option that is gaining ground is a called
the Habeas warrant mark. This requires a license to be
purchased, but it is kind of like the "Good Housekeeping
Seal Of Approval" for e-mail marketers.
Habeas is forming partnerships with emailers and spam
filters to establish credibility and to verify opt-in
emails. SpamAssassin, for example subtracts 4 points from
your score if Habeas appears in the header of your email.
Spam filters are also on the lookout for emails that contain
a lot of HTML and they pay close attention to the links
that are in your content.
For example, if SpamAssasin "reads" that your
email contains more than 50% HTML, you get socked as many
as 1.78 points. Filters are also picky in regard to hyperlinks.
Want to get a quick3 points added to your score? Just
have a link with the IP numbers and not the domain name.
The ability to unsubscribe is also a target of spam filters.
It is best to avoid using lines such as "Click here
to unscubscribe" and "Use this link to".
Apparently, this is a tactic that many genuine junk-emailers
use to give the appearance of their messages being legitimate.
The best way to do this is to this is to ask that your
respondents send a separate e-mail to a separate address
asking them to be removed from a list.
As for the larger Internet Service Providers, (for example,
MSN, Earthlink, YAHOO!, Hotmail, and AOL), they seem to
have their own personalities when it comes to Spam Filters.
Some would be considered more of strict "gatekeeper"
than others would.
MSN, in their policy, states specifically that, you (the
sender or the receiver) may not use or contain invalid
or forged headers or use or contain invalid or non-existent
domain names. They go on to say that "if Microsoft
believes that unauthorized or improper use is being made
of any MSN Service, it may, without notice, take such
action as it, in its sole discretion, deems appropriate,
including blocking messages from a particular Internet
domain, mail server or IP address." So basically,
if MSN doesnt like it it doesnt get
The Earthlink filter system has been dubbed as "too
much of a challenge" by some. This ISP uses what
is known as a "Challenge-Response" system. The
filter device requires senders to prove they are human
rather than an automated program. When a recipient gets
e-mail from an unknown sender, Earthlink software automatically
returns a message -- a challenge -- requiring the sender
to perform a task such as filling out a form. The idea
here is that a "blast" program cannot answer
the challenge, so it must be spam!
Yahoo and Hotmail make use of a system by Nullifier Pro,
which claims to block 99% of unwanted junk e-mail with
zero false positives (yeah right)! Each incoming E-mail
is analyzed for semantic identifiers of words and phrases
based on the message, its attachment, subject and header.
It features automatic spam definition library, foreign
spam blocking, and friends list and advanced abuse reporting,
but most of the time it just ends up in a "bulk"
AOL recently added new spam filters that are being advertised
as able to "grow" with each users preference.
This particular filter "grows" or learns"
by the AOL subscribers reporting spam to AOL, which then
"pools" these into one big database for their
online community as a whole and for the individual member
individually. When AOL talks, people listen because of
the large subscriber base, so this one will be one to
watch. Only time will tell if this is "truth"
It is really still the dawn of Internet marketing. Congress
may in the future pass some kind of e-mail "fees"
expect the post office to push for something like
a use tax or "stamp price" for e-mails as they
are loosing billions in revenue in mail that is not sent
through their system.
It is still hard to beat the cost to benefit ratio of
email marketing. The response rate does not have to be
all that high for the mailing to be considered profitable
since it really costs little more to send 20,000 emails
as opposed to 100 emails.
Therefore, email marketing is and will continue to be
a tremendous "bang for your buck", and a wonderful
tool of choice for the professional marketer.