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Spam filters and professional email marketing

November 11, 2009

The problem of spam has reached such endemic proportions that a whole new industry has grown up around the problem of tackling it. Anti-spam vendors are battling it out to gain a lead in the marketplace; offering ever more sophisticated solutions - many of which lie in filtering out spam before it even gets to the user.

This month we focus on anti-spam technology, we examine the techniques that are being used and what impact they might have on the legitimate email marketer...
Most marketers would agree that the escalation of spam is becoming such a problem that it jeopardizes the very existence of email as a useful marketing tool.

Email marketing is one of the most effective ways in which to reach new customers and keep in touch with existing ones. Many however, believe that spam is spiraling out of control, despite the best efforts of governments around the world, and is making commercial email more of a hindrance than a help.

As a result more and more companies are looking for individual solutions to minimise the amount of spam in their mailboxes and a variety of filtering software solutions are developing in order to satisfy this growing market. The problem is, not just spam is being filtered or blocked by such software - messages people actually need or want are being blocked along the way. Often neither sender nor recipient is alerted to this fact and you may not even realise that it is happening.

So, how does this filtering technology work - and is there anything that email marketers can do to prevent their genuine communications getting caught in the net?

How it works 

Most email filtering or blocking solutions work by checking email for a range of features or characteristics deemed more likely to signal that the email in question is spam. If it finds that an email shows more 'probable' spam characteristics the email is blocked. In some cases these 'blocked' emails are sent to a separate folder that the user can (but probably doesn't) trawl to pick out legitimate emails. Sometimes however emails don't even make it into a spam folder, they simply disappear into a blackhole never to be seen again.

The filtering rules used are manifold and change on a regular basis as program developers try and keep one step ahead of the spammers. Spammers in turn work as hard at getting round filters as they do at seeking out and bombarding email accounts. There are a number of software vendors that offer bespoke filtering programs but increasingly ISPs are offering filtering as part of even the very basic packages in an effort to attract more customers.

As well as filtering, some companies also operate blacklists and whitelists - lists of domain names and IP addresses that are either instantaneously rejected (blacklist) or accepted (whitelist). Getting blacklisted is obviously a move to avoid.

What characteristics are filtered out? 

The list of characteristics that filters consider demonstrate a high likelihood of spam is long and constantly changes. Many of them are obvious and unlikely to affect the legitimate email marketer - unfortunately a large number may also trigger a block on the most innocent email that your customer has opted into receiving.

Danger points that you should be able to avoid include:

  •  Addressing an email to a large list of people, such as bcc list 
  •  Text in the body of an email that contains a lot of lines written    entirely in caps, or with a large number of exclamation marks

These seem easy to avoid - and are clearly examples of the most dubious sort of spam most people have received at some point or another. Some filtering traps however are not so easy to dodge.

According to the website Spam Assassin the following are marker points on some popular filtering programs that will flag an email up as possible spam - some of these are genuinely difficult to avoid using, particularly if you are sending an enewsletter:

  •  A subject line that talks about savings
  •  An html link that says click here

Body text that contains a passage offering to remove the user from the list if they do not want to receive any more email. (UK law now states that all direct marketing emails must provide the recipient with an easy means of refusing further communication by email - so it is virtually impossible to avoid this one)

Delivery methods can also trigger a blocking response. If, for example, a mass email send-out is detected some ISPs will take this to indicate spam activity and blacklist the sender.

Email marketers running legitimate, permission based campaigns can unwittingly fall foul of these rules (and there are a great many more besides). The best email offer in the world will fail if the message, subject line or method of delivery falls foul of a filter along the way.

Triggering a 'false positive' that sends the message to a bulk folder or to the virtual spam bin makes the whole process a wasted effort.

What can I do to avoid triggering the filters? 

Fortunately there are steps you can take to minimise the risk of your message being filtered out along with the trash. Here are our top tips to avoid being dumped:
Constantly monitor campaigns: look out for a low delivery or open rate. This could indicate that your domain has been blacklisted

Make sure your email servers are properly set up. In some cases this may mean talking to your email service provider, basically you need to make sure that your email really comes from where it says it does.
Avoid continuing to send messages to invalid email addresses. Monitor bounces and update databases immediately

Do not send mass messages using the bcc field in your email software. It is better to deliver email campaigns in smaller chunks rather than trying to hit hundreds of customers simultaneously (you'll be better able to deal with responses this way in any case).

Try not to use words such as FREE in the subject line, avoid excessive use of exclamation marks and capital letters in the subject line and body of your message.

The best way to get around filters is to use best practice throughout your campaign - from the acquisition of addresses, creative elements, delivery and response management.

Make sure you have permission to send the email, make it useful and relevant to the user and deliver messages according to their needs and expressed preferences.

Marketers who respect their customers and operate genuine permission based campaigns should not have anything to worry about. Campaigns should always be closely monitored so that should the worst happen you can respond immediately.

The reality of the era of spam is that some of the anti-spam solutions being used present legitimate marketers with an additional problem to be aware of when planning and running a campaign. If, however, best practices such as those we have discussed in previous newsletters are followed every step of the way, the chances of your email being mistaken for junk mail should be slim.

If you need any further information please email [email protected] or call 0161 817 2929

Posted by Simon Hill

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