If you hang around where business people (this includes authors) talk about marketing, the topic of mailing lists will come up a lot, and every so often someone will ask about email verification services. These are companies that, if you upload a list of email addresses, will tell you which emails are valid, junk, dead, etc. Most charge for this service, raising the question of whether putting your mailing list through are worth the expense.
I've just used one of these services, and I can tell you that the answer is a very firm "it depends".
No, seriously, this type of service is only useful in certain situations, and almost all other cases it is a waste of money. For example, it is a good way to clean junk email addresses before you add them to your mailing list, but it is of little use for an active list that you are already sending emails to.
Let me explain how I found that out.
I am in the middle of relaunching this blog for its ninth anniversary, and one of the things I am doing is revamping my mailing list with a new design, schedule, etc. I am actually using two services to deliver my blog posts by email, Feedburner and Mailchimp, and I want to drop one.
I'd been wanting to get rid of Feedburner for a while now because it is lacking in features and no longer supported by Google. (There are in fact a whole host of reasons to leave Feedburner, as Jane Friedman explains in detail.) But before I leave Feedburner, I need to make sure that it is worth the effort to move the email addresses. Feedburner doesn't offer any type of analytics, so I really do not know whether any of the emails were valid, junk, or dead. This is an important details because it's not worth moving dead or junk email addresses. (Also, email services like Mailchimp will ding you if you import a list with a high percentage of bad email addresses.)
And so I turned to QEV, an email verification service I had previously tested. They will check up to 100 email addresses a day for free, but that's just not a high enough volume, so I signed up for a monthly plan that would let me check up to 500 emails per day (I'm going to cancel as soon as this project is done).
Over the past few days I have been feeding my Feedburner list into QEV, and once that was done I grabbed a random 500 different email addresses from my list on Mailchimp and fed that in as well.
Now, when you use a service like QEV, they're going to tell you that an email address falls into one of four groups. The groups will vary between one email verification service and the next, but for QEV they include:
- Safe to send - These are the email addresses that QEV knows belong to real people. This group will often come back from QEV with real names and mailing addresses attached.
- Valid - According to QEV, this group of emails should work but that is all they can say.
- Invalid - These are the email addresses that QEV believes lead to dead inboxes because technical tests showed there was no mailserver to receive the email.
- Unknown - Email addresses in this group might be valid, or they might not. QEV can't tell for sure, so they don't charge a fee.
QEV advises that you only use the "safe to send" group because that is the one that is most likely to end up in front of a real person. If I were using this list for marketing, I would likely follow their advice because that's the group most likely to buy something. But since these email addresses belong to people who were my readers more than potential customers, I decided it was better to keep all valid email addresses.
Here's what I found when I ran my tests:
- The vast majority (98%) of the list from Mailchimp was made up of valid email addresses. The rest were unknown, which in this case probably means that the email addresses are valid even though QEV can't say for sure.
- The Feedburner list, on the other hand, wasn't nearly as clean. Over 16% of the emails in my Feedburner list tested as either invalid or unknown.
Mailchimp had already been cleaning my list as I was sending out emails,. They had removed email addresses whenever an email bounced or was rejected, so there was little reason for me to spend any time or money checking the rest of the emails from Mailchimp.
Feedburner, on the other hand, did not bother with cleaning the list, so I really should do that when I move the list from Feedburner.
What this has taught me is that a service like QEV has value in inverse proportion to the quality of my list. Reputable email companies like Mailchimp already clean your list, so there's little reason to pay QEV to do it. (On the other hand, QEV can tell you more about your subscribers, and that might be worth it.) Email addresses bought from lead generation services or scraped from the web have no guarantee of quality, so you should run them through a service like QEV.
Really, though, the only way to know if your list is high-quality is to test a sample, and check the results.
Luckily, most email verification services like QEV will let you test a limited number of email addresses for free.