While metrics are an invaluable marketing tool, they also can provide a false sense of comfort.  As an example, your email marketing delivery rate may not be telling you exactly what you need to know.

Email deliverability is obviously critical – if someone doesn’t get your email marketing message, they can’t read it and act upon it.  However, the standard ‘deliverability rate’ provided by many email service providers doesn’t tell you the full story. Often, the number of emails delivered that is reported only reflects those messages not rejected by an ISP.  The deliverability rate may only be reflecting issues such an inbox being full or an email address no longer being valid; it doesn’t tell you how many emails actually make it to your subscribers’ inbox. 

After the ISP (or corporate email server) accepts the email, it may still determine that the message is spam and place it in a junk or spam folder.  In a recent ISP email deliverability study (pdf), Lyris found that Yahoo sends about 26% of messages to the junk folder and Gmail and Hotmail send about 18% each.

You need to make sure you understand whether your email service provider reports on deliverability to the inbox.  If not, you have a couple of options.  One approach is to sign-up for email accounts with major providers (e.g. Hotmail, Yahoo Mail, GMail, etc.) or using existing personal accounts and then send your campaigns to those ‘seed email addresses’ in addition to your regular subscription list and monitor whether the email sent to the seed addresses are blocked, sent to the junk folder or make it to the inbox.  Another approach, which I recommend, is to use a service like DeliveryMonitor.com, Return Path, or Habeas to track deliverability to the inbox.  These services, which vary in cost and functionality, track and report deliverability to the inbox.  DeliveryMonitor, for example, is very inexpensive but still provides results across a large number of ISPs.

If you haven’t checked your inbox deliverability recently, now is the time.