Email Deliverability for Marketers

If you're still sending your own mail using you're company's email server, it is time you switched to an Email Service Provider (ESP). ESP's have entire staff dedicated to keeping their customers' email deliverability rates high.

When you send an email message to a customer it is sent from your mail server to a receiving mail server, hosted by their company or an ISP, before being delivered to their inbox. ISP and companies use a variety of rules to determine whether the inbound mail their mail servers receive is legitimate or if it is spam.

The deliverability staff at an ESP understands these rules which are different at every ISP and many companies and they tune their mail servers to respect them. For example, the ISP BellSouth.net prefers to receive inbound mail at a limited rate. People who try to send mail to BellSouth.net at a faster rate will have some or all of their mail messages blocked them, regardless of the content of those messages.

In addition, an ESP's mail servers are specially configured using a variety of methods so that ISPs and companies can distinguish them from mail servers that send spam. ISP's also establish special white listing and feedback loop relationships with ESPs that yield higher deliverability rates.

Every month, remove the email addresses of all the people on your list who have not opened a message in the past three months. This may seem obvious, but a lot of marketers don't do this. Your open rate will increase significantly, your mailing costs will drop and you'll avoid the following deliverability issues that can occur if your repeatedly send email to addresses that are no longer active.

ISPs penalize mail servers that send a lot of mail to email addresses that have expired by blocking legitimate addresses that are part of the send. If you are using an ESP, the ESP may already be removing email addresses from your list that are no longer active. and if not, you should be doing this yourself.

ISPs also keep a list of expired mail addresses and domains that are called spam traps. These email addresses are harvested by spammers from old web sites. If your list contains these spam traps, all of the mail sent from your mail server to the ISP may be blocked because the ISP thinks you are a spammer.

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If you have access to bounce messages, they can give you a good idea why your email messages are being blocked. When a destination mail server blocks or filters your messages, it sends back an SMTP response. Often, this response will provide an explanation for the delivery failure.

Sometimes these messages can be very ambiguous and difficult to interpret. But certain types of bounces such as an expired mail address, an unknown user, or a spam classification block are easy to pick out. In addition, bounce messages will also show you if your mail server has been blacklisted in a spam database.

Spammers set up mail servers for a short period of time at an IP address, blast out mail, and then move to another IP address. If an ISP does not receive email continuously from your mail server, it may very well assume that your mail server is sending spam. This is a problem for smaller companies that manage their own mail servers and another reason why you should switch to an Email Service Provider.

While Email Service Providers provide clients with the option of having their own dedicated IP address, this practice will backfire is you are not sending out a continuous stream of email campaigns. You are better off to share an IP address with other reputable businesses who together provide enough aggregate volume to appear to ISPs as a legitimate mail source.