Recently, we helped a client who didn't realize at first they had a problem. They were cruising along with a successful and innovative email marketing program, unaware that they were about to hit a snag. A big snag. And then it happened: They found out they were being blocked by a major ISP. They did not realize at first that they were being blocked and didn't know what they had done to cause the problem.

They asked ClickMail to help them sort out the issues, and we did. It reminded us once again of the importance of monitoring.

In email marketing, you don’t know what you don’t know. A lot of what happens after you’ve launched an email campaign is hidden from view. That makes monitoring critical. You could be doing almost everything right. You could be enjoying a great email deliverability rate, and a high ROI. Then suddenly, it will all go south.

Monitoring prevents that, because it brings to your attention what you would have missed on your own. It empowers you to keep your sending reputation clean and to find and fix small problems before they become big—and costly—ones.

Things can change from one day to another. What renders properly today won't necessarily render properly tomorrow. Likewise, what is delivered today may not be delivered tomorrow.

If you're not keeping an eye on key metrics:

One thing you probably would know: Your email marketing ROI would start on a downward trend! Because most, if not all of these factors impact your deliverability to the inbox, and therefore the number of potential conversions.

Don't assume no news is good news; things change without you knowing. Do you remember what happened when Microsoft changed from using Internet Explorer as the rendering engine for Outlook 2003 to using Word for Outlook 2007? Disaster!

And now the deliverability game is changing even more, as ISPs are starting to look at people's behavior and how they interact with your email. Major ISPs are going to decide if your email is spam based on the recipients interaction, or lack of it, with your communication. You have absolutely no control over that. So you'd better be keeping an eye on your metrics!

Although the best monitoring is done by a professional team, you can tap into the following resources to keep your eye on your deliverability.

You can check your sending reputation using Sender Score or SenderBase. Sender Score aggregates data from 60 million mailboxes at a variety of ISPs, spam filtering and security companies. SenderBase is the world's largest email and Web traffic monitoring network, and can be used like a "credit reporting service" for email.

You can get more in-depth information about your reputation from Pivotal Veracity. Pivotal Veracity also offers several other tools for monitoring your email, from rendering issues to how recipients interact with your email once it hits the inbox.

Next, set up a schedule for monitoring your reputation, and stick to it. Check at least monthly, but not less frequently than every quarter. It only takes five minutes to review the feedback you get regarding your reputation, although it is important to know how to read them.

Another way to monitor your email deliverability (and rendering) is with free email accounts with major ISPs like MSN, Gmail and Yahoo. Create these accounts and add them to your seed list, so when you do test sends, you can see real results.

Monitoring your email to avoid disasters is necessary but not complicated. The most important thing is to just do it, regularly. However, if you're unsure about your ability to get the right information and interpret it correctly, or if staff resources are maxed out leaving no one to take on this additional task, you can outsource this critical task.

You simply can't risk not knowing.