Comment Spotlight: Open Rates and Image Blocking

I read an article on Problogger this week that talked about different ways to respond to comments, including responding in a separate blog post.

This is a great way to make sure as many people as possible benefit from discussions that they might have missed in a post’s comments, and something we should have started doing a while ago. (Thanks for the reminder, Darren!)

For our inaugural Comment Spotlight, I’d like to address an important point about tracking your message open rates:

How Does Image Blocking Affect Open Rates?

In response to our post on MarketingExperiments’ study on different styles of HTML message, Shiva asked:

“Doesn’t anybody face the problem of images being blocked? In Gmail and Yahoo the images in the html mail are blocked by default, and the user has to explicitly click on a link like “Display images below” to see the images. Doesn’t this affect the open rates of html mails? Could you please address this?”

Shiva’s absolutely right β€” if a user has images disabled, the one-pixel image used to track message opens won’t be displayed, and an open won’t be recorded for that user.

On top of that, if you have readers who scan messages using a preview pane, and they have images enabled, you could be recording opens for people who aren’t actually reading your messages.

So… what does this mean for you as you look at your stats?

It’s Not Where You Are, It’s Where You’re Going That Matters

You might think that since some people read your message but don’t record an open, and other people do record an open, but don’t actually read your message, that open rates are useless.

And to be honest, if open rates are all you use to track the effectiveness of your messages, and if you’re only looking at open rates in absolute terms, then well… they probably are useless.

If, on the other hand, you:

  • Compare them to your clickthrough rates
  • Track changes in them over time

then they are quite useful, primarily to identify trends in subscriber responsiveness. For example:

  • If your open rate falls over time, it may mean your subscribers are beginning to ignore you β€” but why? (Are you not providing the same value? Are your subject lines not getting their attention?)
  • If your proportion of clicks-to-opens increases over time, it may mean that your message body is doing a better job of spurring readers to action.

Open Rates Tell You The Most In The Short Run

The key assumption in reading into those trends is this:

For a given group of subscribers, even if you don’t know how many people are blocking images, or how many have them enabled but don’t actually read your message, the proportion of each group isn’t likely to change much in the short run.

A year or two from now? Sure, it’s quite possible that a different proportion of your readers will be blocking images, or will have them enabled but not actually read your message. So I wouldn’t compare your open rates from 2005 to today and expect to deduce anything significant.

But let’s face it: “In the long run, we’re all dead.”

Use open rates to measure subscriber response and improve your email marketing campaigns in the short run, so you’re still around for the long run.


  1. Diana Fontanez

    8/21/2007 3:13 pm

    Hi there Justin!

    A week ago I received, from Jupiter Research, information about the email marketing industry in regards to delivery rates, open rates, clickthrough rates and conversion.

    – 88% of delivery rate
    – 20% open rate
    – 9.5% CTR (clickthrough rate)
    – 1.1% convertion rate

    In essence, what this information tells us is that if we have a list of 10,000 people, on average, 8,800 will receive it. 1,760 will open it, 167 people will click inside the email and 1.1% will buy.

    This is industry averages and very discouraging for the businessperson who is not familiar with the email marketing industry yet uses it as a way of communicating or selling his products or services.

    That is what my Spanish article explains. That if we increase delivery rate or open rate, we might be able to influence CTR. Which is the objetive TOGETHER with our convertion rate.

    So the whole point here is to work on open rates WITH a major focus on clickthrough rate and conversion rates. πŸ™‚

  2. Justin Premick

    8/21/2007 3:37 pm

    Hi Diana,

    Thanks for bringing that up!

    I agree – if you can get more of your readers to open and read your message, you’ll get more of them clicking through, and more of them purchasing from you or taking other desired actions.

  3. Ameen Kamadia

    8/22/2007 11:21 am

    In a recent seminar, the editor of the daily email newsletter Early To Rise commented that they have a 30% open rate. Keep in mind they mail out every day and have several thousand subscribers.

    I thought this was a little high. Most marketers I have talked to mention a closer to 20% average in open rates.

    Thanks for that tidbit Diana.

  4. Diana Fontanez

    8/22/2007 11:49 am

    Hi there, Ameen

    I also read Early to Rise. Yes, they publish a daily newsletter. They also have a great team of editors, writers, and make good mula.

    I believe that their 30% open rate is due to the different topics they cover (health, entrepreneurship, and investments).


    I have a 47% open rate but my list is small. I also have a bigger list and im on a 27.9% open rate average.

    That is why i liked Jupiter Research’s data. It sort of puts you at ease knowing that it is ok to have a 20% open rate. That it is ok to have a 9.5% clickthrough rate. We just need to work on increasing those percentages. πŸ™‚

    (note: i am not trying to sound like the guru from heaven. i just love email marketing and have been educating the hispanic industry for over 8 years).

  5. Roger Haeske

    8/27/2007 8:50 am

    On 12/14/06 I had an open rate of 123.9% to a brand new list of 67 people. Yes I had 83 opens.

    This is troubling to me. This means that Aweber counts all opens even if one person opens up the email 50 times, each time it’s opened it will be counted.

    The same with the clickthrough rate. It would be much more useful if you tracked unique opens and clickthroughs.

    It would also be great if you knew which people on your list actually opened and which clicked through. I’ve had other services that could at least tell me which people on my list clicked through for a particular message.

    On my much larger and older list the best open rate I got was 59.3%. But I’ve noticed in general that my open rates have gone down considerably over time.

    Whereas a good open rate early this year was in the high 40 to 50 percent range, these days the best I get is around a 30% open rate. The problem we’re dealing with here are the multiple factors that affect open rate.

    Yes maybe I have less people opening, and yes the list is getting older and maybe even less people are seeing the graphics displayed in their emails.

    Even clickthrough rate can’t always be so reliable. Because it depends highly on your format. Personally I design my emails to have almost no information except the topic.

    If they want to learn what I’m writing about, they have to clickthrough to the page or just go to my site directly without clicking. This format in general creates a much higher clickthrough rate. (This is a good thing.)

    Since I always use the same link, that might affect the clickthrough rate as well. The reader knows they just have to visit my website, maybe they have my site bookmarked and they get to it without using the link in my email.

    I know this could happen because sometimes I do it with the emails I receive.

  6. Justin Premick

    8/27/2007 11:33 am

    Hi Roger,

    You’re right, we do currently count each open. So if someone opens an email multiple times, or if they forward it to someone else who then opens it also (and of course has images enabled), both of those opens would be counted.

    We’re working on a number of enhancements to our tracking that should address your concerns – if there’s something else specific you’re looking for (besides seeing which subscribers opened & clicked), please drop our Support Team a line detailing what you want to be able to do. That way we can make sure that we’re meeting your needs.

    Your clickthrough rates can definitely vary based on how you design your messages. For that reason, we don’t recommend to users that they shoot for any particular clickthrough percentage. Just like open rates, clickthrough rates are most useful as a relative measure – whatever your design/format may be, if you’re keeping it consistent from message to message, then it’s quite helpful to compare response rates from one message to the next.

    Thanks for sharing your results and insights!

  7. Greg

    9/6/2007 12:22 pm


    If you use Win 2003 as your web/email server, then you easily can track who clicks what in every message you sent.

    I will explain it with an example.

    You create a new message with the title "Things To Do" (ttd for short)

    All you need to do is to assign "?ttd=<%=[Email]%>" to links you want to track. The link will appear something like


    This will present a log report similar to


    As you can see, you can add any argument to your links to track them. Now just run your log analysis app and you’re done.

    Yes, I assume you are using databases and also that you know how to implement the VB code… or at least that you have a programmer doing this stuff for you.


  8. 5 Reasons Email Marketers Should Give Thanks

    11/23/2009 11:02 am

    […] open rates (which are still useful, even if they’re not perfect), to clickthroughs, to conversions, we can use email statistics to see what works, what […]

  9. Marcus Hochstadt

    12/4/2009 8:56 am

    Hi Justin,

    What about your remark above that AWeber would be working on a number of enhancements to the tracking that would address the concern of counting each open vs. IP or receiver based open? Does the system still track each and every open no matter if it’s the same receiver?

  10. Justin Premick

    12/7/2009 10:10 am


    We count both total opens/clicks and uniques, and you can see in your stats which subscriber/s are clicking which link/s. You can also segment your list based on open and click activity.

  11. David Durand

    3/13/2012 11:38 am

    Thanks for the contributions above. You motivated me to share my experience here!

    For my bigger lists my open rates declined, as others have reported above, as my readership went up. The initial subscribers were more connected by having received my email newsletters prior to moving my lists to Aweber, so open rates were at 92% at the 3rd email, and the first email was at 129% from multiple opens by single subscribers.

    The highest open rate with matching click rates that I have seen AFTER my open numbers slumped to the low 30% range was an email with a link to the cause of Mark Haines’ cause of death that I wrote. The headline (email for another site, said “Mark Haines Cause of Death – Case Closed,” which indicates to me that if you entice the reader with exclusive content, they will be much more likely to open your emails.

    I think when the reader starts to guess what you’ll say based on your title and when you don’t mix things up by offering something new in the emails and/or write weak subject lines, you lose opens and click-throughs. Even if it’s “great information,” the reader can get bored. The punch line is that 59% of my subscribers opened the Mark Haines email and 59% clicked through to find out why he died. I’ve had over 85000 visits to my blog to read that one article, which is linked to from a couple of big websites including Wikipedia. Another tip: I emailed two of those sites to urge/nicely compel them to reference my article properly and they did so politely and willingly. Wikipedia was the first to link to the article.

    Keep it fresh! Surprise your readers. They’ll open and click more. But don’t be discouraged if your opens drop to 30% or so or even lower as some have mentioned. Just come up with your next surprise.

    Best regards, David

  12. David Durand

    3/13/2012 11:44 am

    One other question for Aweber. If the image is not shown to the subscriber who opens the email, you said the open is not recorded, but is the click-through via one’s link also NOT recorded? I assume it would not be, but thought I’d ask! One could “record” it oneself of course by using a tracking link rather than a link to the page that provides no tracking. Thanks.
    – David