Mass email tracking

Solution 1:

1. Yes, this is pretty much the only way to do it. Consider that an email is something that is inherently static. The only way to know if someone has "opened" an email is for the email to send some information back to your server. Most email clients these days support HTML emails, which means that you can get the client to request an image (or anything else) from your server by embedding the proper HTML tags. Other than this, you cannot force an email client to do anything it doesn't want to do. It's a separate program on a remote computer, and you have no control over it.

2. No, there's no foolproof way. There will always be emails you can't track. If someone downloads their email and disconnects from the internet before reading it, you can't track that email. Most email clients allow you to disable image loading now as well if you want to, so that can block tracking too.

3. I've usually written my own, so I wouldn't know what to recommend. I imagine most services will be quite similar, so I'd base a product/purchase decision on how easy their front-end is to use.

Solution 2:

In addition to pixel tracking, a second way to track open rates is by looking for clickthroughs. If someone clicked through, then they must have opened it. This is infrequent, but it's important not to throw this data away.

More details:

• How MailChimp tracks open rates
• How CampaignMonitor tracks open rates
• Wikipedia on email open rates
• Hubspot on open rate issues

Solution 3:

Facebook uses a bgsound element in addition to an img element like this:

<img src="http://www.facebook.com/email_open_log_pic.php?mid=999999999999"
                  style="border:0;width:1px;height:1px;" />
<bgsound src="http://www.facebook.com/email_open_log_pic.php?mid=99999999999&s=a"
                  volume="-10000" />

Solution 4:

1. This is the best way, and it's hardly ideal - many e-mail clients block images to start with.
2. No, no methods are foolproof. A foolproof method of detecting if someone had read an e-mail would be a significant privacy issue.
3. I've used ExactTarget and CampaignMonitor's tracking systems. Both worked pretty well for tracking trends - i.e. twice as many people opened e-mail #1 than #2 - but you never know how many missed opens there are due to images not being shown.