We are pleased to have this guest post from Mohammed Ahmed,  Sr. Manager of Deliverability Services for BlueHornet.  See Mohammed at the BlueHornet Lifecycle Messaging Conference October 9th through the 11th, 2013 in San Diego, California.

As the Sr. Manager of Deliverability Services for BlueHornet, I answer and address deliverability questions every day. I’ve found  that deliverability is a mystery for most, so below are some of the frequently  asked questions I receive from BlueHornet clients – from the simplest to the  more complicated.

What is IP/Domain reputation?  

Every ISP has a monitoring system that checks on IP/Domain names throughout the day.   The system looks at your IP/Domain stats — total volume, total invalids, complaints, spam traps, creative, subject line, from address — and assigns a reputation score.

Some companies use the Sender Score service to determine their reputation; however, it’s important to remember that you won’t be able to determine actual scores from each provider using Sender Score.

The major ISPs have their own spam filtering systems and don’t use Sender Score.  As such, if you have a high Sender Score, an ISP may still block your mail. Conversely, if you have a bad Sender Score, don’t freak out; you may have good data and good user engagement on a specific ISP.

If I’m blocked, how long will I be blocked from a specific ISP?

That depends on the ISP – it could be a number of hours, a number of days, and in some cases, your IP or domain name will be hard blocked, meaning that you’ll no longer be able to send to that inbox without further action on your part. Usually, the bounce message you receive from the ISP will tell you what you need to do to get a block removed:  pausing your mailing, opening a ticket with support, etc.

Why I am getting the same bounce even after I’ve paused mailing?

Each ISP has a different rule as to how long it will attempt to resend an email, some will retry a certain number of times, others for a certain duration of time. It’s important that you work with your email service provider; an experienced deliverability expert knows each ISP’s rules and will be able to help you fine tune the pause rules.

Or, your IP may have been unblocked, but your domain is still blocked on that ISP because of a different error code, like spam content in the mail.  In this case, you need to submit a support ticket to the ISP.

I followed best practices and I am still getting email filtered on that ISP, why?

Most likely, your data needs to be better segmented per user engagement (UE).  Check to see how old your data is, and determine the user engagement on older addresses. Chances are it’s low or non-existent.  If that’s the case, start segmenting your data based on UE.  ISPs are increasingly watching UE.

What’s a feedback loop?

A feedback loop is when someone reports an email as spam, and the ISP notifies the ESP. The ESP is able to use that information to remove the subscriber from the database and/or analyze complaint data to re-evaluate messaging and content.

My IPs are white listed and I use a feedback loop, but I’m still getting bounce backs from ISP’s, why?

These days ISP’s may give your IPs/Domain name white list status, but that status is very dynamic.  They only rely on your mailing stats for a number of hours.  Some calculate reputation score every 4 hours, some for a shorter period, and some once a day.  A white list provides some benefits, such as a high  complaint threshold and accepting higher volumes of email, but it’s not a free pass.